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QING-HAO («CHING-HAO»)
and the Artemisias Used in Chinese Medicine
by Subhuti Dharmananda, Ph.D., Director, Institute for Traditional Medicine, Portland, Oregon
Ching-hao refers to the tops of Artemisia annua (the species name refers to its growth as an
annual). The Chinese name (pinyin: qinghao) makes reference to the color green (qing); the dark
green leaves at the top of the plant are the most active portion, which might account for this
designation. The latter part of the herb's name, hao, indicates this type of plant, one characteristic
being a tall stalk; the term is used to depict several other Artemisia species as well. Ching-hao is a
common weed in southern China; it is also distributed in temperate regions across the globe,
including in Europe and North America. There are numerous medicinal Artemisia species used
worldwide, several of them having a reputation for dispelling worms, and hence the group is
commonly called "wormwoods." Ching-hao is sometimes referred to by the English common name
"sweet wormwood" (also known as sweet annie): the aroma is sweet. It is in the Asteraceae family,
and has yellow flowers (see Figure 1).
Ching-hao is markedly bitter in taste, cold in nature, and is classified among the heat clearing
herbs, either with those that treat summer heat or those that treat deficiency heat. Summer-heat
syndromes are so-named because they usually arise during the summer, when contaminated food
and water are prevalent and insect-borne pathogens are transmitted. The syndromes encompassed
by this category correspond to various types of infections and parasitic diseases, often accompanied
by fever and headache. Deficiency heat is a condition usually accompanied by yin deficiency that
involves sweating in response to fever, especially at night. While deficiency-heat syndromes may
occur at any time of year, they are more likely during the summer, when the environmental heat
contributes to the discomfort.
1
Ching-hao was described in the Shennong Bencao Jing (1) where it was listed as caohao:
Caohao is bitter and cold. It mainly treats skin bugs, itchy scabs, and malign sores; it
kills lice, relieves lodged heat in the joints, and brightens the eyes. Its other name is
qinghao.
Based on this brief presentation, ching-hao was primarily used for skin disorders, as a
parasiticide, applied topically; a use that is still made of the herb. It was administered internally for
rheumatic disorders of the hot type. Three other varieties of Artemisia were also mentioned in the
Shennong Bencao Jing: anluzi (Artemisia keiskeanae), baihao (Artemisia argyi; the white hao),
and yinchenhao (Artemisia capillaris, yinchen refers to its growth like a carpet of green); the latter
is commonly called capillaris. The main parts of each of the descriptions are as follows:
Anluzi is bitter and a little warm. It is non-toxic, treating mainly blood stasis of the five
viscera, water qi in the abdomen, abdominal distention, persisting heat, wind-colddamp impediment, and various kinds of pain in the body.
Baihao is sweet and balanced. It mainly treats evil qi in the five viscera, and windcold-damp impediment. It supplements the center, boosts the qi, promotes the growth
of hair, is able to turn the hair black, and cures heart suspension [a syndrome involving
reduced eating and constant hungering].
Yinchenhao is bitter. It is nontoxic, treating mainly wind-damp-cold, and hot evil qi as
well as bound heat jaundice.
For each of these three, but not ching-hao, an immortality benefit is also given, such as
"Protracted taking may make the body light, boost the qi, and slow aging." The ability of ching-hao
to "brighten the eyes" may parallel these claims rather than being a specific indication for treatment
of poor vision: dulling of the eyes is noted as a sign of aging and mortality in some classic texts.
The main area of overlap between the four herb descriptions is in the apparent ability of each to
treat joint pain. For ching-hao, this indication is heat lodged in the joints; for the other three it is the
wind-cold-damp syndrome, which is one that often manifests as arthralgia. Despite these
indications, the Artemisias are rarely included in important traditional formulations for treatment of
the bi syndromes (the disorders that include arthralgia). Instead, some other applications of the
herbs have become more important.
In addition to the Artemisia species of medicinal herbs described in the ancient Shennong
Bencao Jing, there are several others used in Chinese medicine. The main ones are the following
two (2):

aiye (first described in the Mingyi Bielu, ca. 500 A.D.), which is the material used for
moxibustion; it is valued for internal use as well. Aiye is bitter, acrid, warm, and used
to warm the uterus, control bleeding, dispel cold-dampness, and control pain. It is
often included in formulas for women's problems, such as cold pain in the abdomen,
menstrual disorders, leukorrhea, infertility, and tendency to miscarriage.

liujinu (first described in the Tang Bencao, 659 A.D.), which is said to be bitter and
warm, used to promote blood circulation, disperse swelling, and relieve pain (like
2
aiye, it is particularly used for women's problems: abdominal swelling, amenorrhea,
and post-partum blood disorders).
Traditional Formulas With Ching-Hao For Internal Use
Ching-hao is an ingredient in a small number of well-known traditional formulas. The ones most
often referenced in modern texts are the following two indicated for deficiency-heat syndromes,
Qinghao Biejia Tang and Qinggu San (3), which are both described below.
Qinghao Biejia Tang (Ching-hao and Turtle Shell Combination)
Ching-hao
6g
Turtle shell
15 g
Anemarrhena
6g
Rehmannia, raw 12 g
Moutan
9g
Turtle shell (biejia) is sometimes referred to in English as tortoise shell; the material used in
this formula is differentiated from guiban, which is similarly referenced as either turtle or tortoise
shell. Qinghao Biejia Tang, prepared as a decoction (tang), is indicated for advanced febrile disease
reaching the blood level and consuming the yin; the formula nourishes yin and clears deficiency
heat. Referring to this formula and the role of qinghao, Wu Tong, in his Qing Dynasty text on
Warm Diseases, said (11):
One of this formula's excellent features is that it can first enter and later exit. Chinghao is normally unable to enter the yin aspect, but can be led in by turtle shell; turtle
shell, by itself, is unable to exit to the yang aspect [to go to the surface], but can be led
out by ching-hao.
This description involves the idea that the pathogen, which started at the surface and then
penetrated to the deepest levels of the body, must be engaged and led back out of the body. Turtle
shell is heavy and thick and lacks fragrance, so it can easily sink into the deeper levels; ching-hao is
light and aromatic, so it can easily float to the surface. The two substances taken together can get
into the deep levels, engage the pathogen, and bring it to the surface for release.
Another benefit of ching-hao in this context of clearing deficiency heat is its gentle nature,
described by Qin Bowei, one of the founders of modern TCM (6): "Many [heat-clearing] medicinals
that are bitter and cold inhibit the stomach and spleen; however, ching-hao is aromatic and pleasing
to the spleen, and does not attack the harmony of the middle qi." Ching-hao is one of the six herb
ingredients of shen-chu (pinyin: shenqu), a composite of fermented wheat and herbs used to
improve the functions of the stomach and spleen and to treat syndromes of summer heat. The
related herb capillaris is also deemed very useful in treating heat syndromes (specifically, dampheat) while benefiting the stomach and spleen. A typical application is treatment of hepatitis with
jaundice in persons who have the complication of digestive disturbance with diarrhea.
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The other formula in this category of deficiency heat therapies is:
Qinggu San (Powder for Clearing Heat from the Bone)
Ching-hao
Turtle shell
Anemarrhena
Stellaria
Picrorrhiza
Chin-chiu
Lycium bark
Licorice
3g
3g
3g
5g
3g
3g
3g
2g
Qinggu San is used for feverish disease in the initial stage when there is pre-existing yin
deficiency. It is particularly used when there is high fever, fluctuating fever, and night sweating.
The formula is a powder, which is why the dosage description looks so different from that for the
previous prescription. There is also a formulation commonly mentioned for gallbladder damp-heat
based on use of ching-hao:
Hao Qin Qingdan Tang (Decoction of Ching-hao and Scute to Cleanse the Gallbladder)
Ching-hao
Scute
Bamboo
Pinellia
Hoelen, red
Citrus
Jasper jade
6g
9g
9g
5g
9g
5g
9g
This formula is aimed at treating damp-heat in the gallbladder and also pervading the shaoyang
(liver/gallbladder) channels, particularly when there are alternating fever and chills, with fever more
severe than chills. This syndrome may include malaria. In this formula, ching-hao serves a role akin
to that of bupleurum in Minor Bupleurum Combination (Xiao Chaihu Tang), a formula with similar
therapeutic action used for a related syndrome. Like bupleurum, the aromatic component of chinghao is said to relieve surface fever and the herb gently regulates the flow of liver qi to improve
gallbladder function. Hao Qin Qingdan Tang is widely used in modern China (often modified for
specific disorders). It has been administered for treatment of high fever of unknown origin and for
cholecystitis (capillaris is more frequently mentioned than ching-hao in traditional formulas for
gallbladder diseases).
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Two of the Artemisias-aiye and liujinu-are primarily used in treating gynecological disorders,
particularly for those cases where there is excessive menstrual bleeding. A well-known formula is
Tang-kuei and Gelatin Combination (Xiong Gui Jiao Ai Tang), which includes aiye. Ching-hao is
not often selected for this purpose, but is an ingredient in the following traditional prescription for
excessive menstrual bleeding in cases of blood heat syndrome:
Qing Jing Tang (Channel Clearing Decoction)
Ching-hao
Moutan
Peony
Hoelen
Rehmannia
Lycium bark
Phellodendron
10 g
15 g
15 g
5g
15 g
25 g
3g
The ingredients in this formula, as in the formulas listed above, are directed towards a
syndrome of deficiency heat, with rehmannia, lycium bark, and phellodendron being characteristic
components of such treatments.
Modern Studies
Ching-hao is mainly obtained from Artemisia annua, but this is not the sole source: it is also
obtained from A. apiacea, A. scoparia, and other Artemisia species that are collected locally for
ching-hao in different parts of China. In Taiwan, Artemisia capillaris (yinchenhao) is used as a
substitute, which also illustrates the similarities of these two species that are differentiated in the
Materia Medica. Chinese investigations have concluded that only Artemisia annua should be used
for ching-hao when its application is dependent on content of artemisinin (see below), which is not
found in all species (27).
All of the Artemisias are fragrant herbs, having essential oils comprised of mixed terpenes,
with the highest concentration in the flowers. The herb is usually collected when in full bloom.
Various species of Artemisias have essential oil contents ranging from 0.15 to 1.0% (30). The
primary fragrant component of Artemisia annua is the monoterpene artemisia ketone (see Figure 2),
accompanied mainly by other monoterpenes (see Table 1). To retain these compounds in a
decoction, it is recommended that the herb be decocted for no longer than 5 minutes (7). These
aromatic compounds may contribute some of the antibacterial effects when applied to the skin, and
are probably responsible for gallbladder regulating effects of ching-hao (as well as those of
capillaris).
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Table 1. Essential Oils in Artemisia annua (29). All items specified are monoterpenes, except
caryophyllene, a sesquiterpene. Artemisia ketone is unique to Artemisia species, but most of the
other components of this essential oil are also found in magnolia bark and flower bud.
Component
artemisia ketone
1,8-cineole (eucalyptol)
myrcene
linalool
caryophyllene
pinene
camphor
borneol
others
Percent of
Essential Oil Fraction
66.7
5.5
3.8
3.4
1.2
0.9
0.6
0.2
17.7
One of the largest research efforts undertaken for any Chinese herb was that pursued for the
powerful antimalarial effects of ching-hao active components (31). An extensive screening of more
than 200 herbs, selected on the basis of their use among 2,000 traditional prescriptions for treating
malarial symptoms, was carried out under the direction of Professor Yu Youyou in Beijing. In
October of 1971, success was achieved when a new type of sesquiterpene lactone was isolated from
Artemisia annua; it was called qinghaosu (su = single ingredient; the term used for isolated active
components of herbs). This discovery helped resolve the problem of drug-resistant malarial strains,
since those strains were susceptible to treatment by qinghaosu. Considerable work over the next
decade was required to bring the laboratory finding to clinical practice. The importance of this
finding is illustrated by the fact that six articles appeared in a single quarterly issue of the 1982
Journal of Traditional Chinese Medicine (English) on qinghaosu and its derivatives, describing
chemical, pharmacological, and clinical evaluations.
The compound (see Figure 3) was later named artemisinin (alternatively: arteannuin). It is
found in the leaves, making up a maximum of about 0.5-0.6% and is highest when the plant is in
flower, which is the time traditionally recommended for collection of the herb. However, the
amount in different plant samples varies markedly, with some specimens of Artemisia annua having
little or no detectable amounts. For example, plants collected in the U.S. typically have very low
levels (29). Most of the artemisinin is localized in the upper leaves (see Table 2).
Table 2. Artemisinin levels in different parts of the plant (29).
Plant Part
Upper third
Middle third
Lower third
Side shoots
Artemisinin as
% of total in plant
41.7
25.0
22.2
11.1
6
Stem, roots, and seeds
0.0
The mechanism of action of artemisinin on the malaria parasite, Plasmodium, has been largely
determined. The parasite, which resides in red blood cells, becomes exposed to cytotoxic free
radicals and reactive aldehydes produced by the action of artemisinin within the iron-rich
environment of the cells. These generated compounds damage the Plasmodium internal membranes
and strongly reduce its ability to gain nutritional components required for growth. Thus, the
parasites die. The effect is prompt; the parasites are nearly gone within two days when using an
effective dosage.
Work has progressed-in the attempt to find more effective antiparasitic compounds-to
production of a variety of synthetic derivatives of the sesquiterpene lactones of ching-hao. The main
ones, artemether and artesunate, have been subjected to considerable study and development for
drug use worldwide.
Using Ching-Hao Derivatives For Malaria
During the early 1980s, the World Health Organization (WHO) undertook a process of evaluating
which antimalarial treatments to recommend for the developing countries where this disease is
endemic (28). Artemisinin was considered, but the data available at the time were insufficient to
convince authorities of its suitability. There were problems with stability of the drug, questions
about an effective method of drug delivery, and concerns about long-term effectiveness (recurrence
of disease). The WHO recommendation was to rely on the modern drug therapies, such as
chloroquine. The primary user of artemisinin and related compounds for treatment of malaria was
Vietnam; the compounds have also been administered in China and Thailand. The malaria problem
in Vietnam, which was severe after the Vietnam War, has largely been resolved. This improvement
has been attributed, in part, to use of artemisinin as a therapeutic agent (32). It is now proposed that
this therapy be used in Africa, where a drug-resistant malarial epidemic is looming: there are about
100 million cases of malaria in Africa each year-90% of all the worldwide malarial infections, with
nearly 2 million deaths each year.
Currently, most of the problems with stability, delivery, and efficacy of artemisinin have been
resolved. Artemisinin was also declared as effective as chloroquine in monotherapy for malaria.
Unfortunately, once the WHO became convinced that artemisinin would be of value, it ran into
problems with the Chinese government, which acted, understandably, like a drug company: the
negotiations for organizing full scale clinical testing, sound manufacturing practices, and rights for
use collapsed (33).
Still, WHO has approved the use of synthetic derivatives, produced in Europe, to be used in
cases of drug-resistant malaria, especially the chloroquine resistant malaria that has developed in
Brazil and parts of Asia as a result of such widespread use of this drug. The most common method
of treating chloroquine resistant malaria is a combination of modern drugs, a method considered
more reliable than administering ching-hao compounds, at least in avoiding recurrence of the
disease. Thus, even when using artemisinin for drug resistant malaria, it is most often recommended
to be given in combination therapy with drugs. For treatment of multi-drug-resistant malaria,
artemisinin derivatives (artemether or artesunate) plus mefloquine is recommended; this
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combination treats the liver stage of malarial parasites, which allows the treatment time to be short
(16, 19). A dose of 600-640 mg of the artemether or artesunate plus 1,250 mg of mefloquine over a
two day period is often effective.
Artemisinin has been subjected to recent testing in uncomplicated malaria (infection is usually
by P. falciparum and the disease is referred to as falciparum malaria). An effort has been made to
determine whether this single therapy might be a suitable substitute for the combination drug
therapies. Adult dosing at 500 mg/day (first day: 500 mg is given twice for a loading dose) for 5-7
days was tried (15). Parasite clearance usually occurred in the first two days. However, the disease
returned with high frequency. In early Chinese clinical studies of artemisinin for malaria, the dosage
given was 800-1,600 mg/day for three days, so the dose used in this study was probably too low to
assure full clearance of the parasites.
It has been suggested that high dose artemisinin (20 mg/kg body weight; typically more than 1
gram per day) for 2 days be followed up with quinine (30 mg/kg body weight) for 3 days to lower
the recurrence rate, which appeared successful in one study (17). In another evaluation, artesunate
was administered in cases of uncomplicated malaria using a dosage range from 400-800 mg by oral
administration of tablets (14). As little as 400 mg in three days was sufficient to clear parasites and
remove symptoms; parasite clearance took place in the first 16 hours. However, 39% of cases
treated that way had recurrence within one month; at the highest dosage of 800 mg for 7 days, the
recurrence rate was dropped by a factor of 10 to 3.9%. Therefore, high dose treatments, as well as a
sufficient course of therapy, may be essential to avoiding recurrence as well as avoiding
development of resistant strains (33). By combining artesunate with mefloquine, the recurrence rate
can decline to 2% (18), though this level of effect has been claimed for high dose artesunate alone
(31). Artesunate is available in injection form and in suppository for rectal administration in
patients with advanced disease. One of the proposed uses of it is for treatment of severely
debilitated patients in remote areas as an initial therapy before they can be treated by the modern
drugs.
Although ching-hao as a crude herb is not as often used today for treating malaria (being
replaced by various preparations of the active components), there is information about the method
for using it. The dosage of ching-hao recommended to treat malaria is 20-40 grams of the dried herb
per day in decoction. In one trial, three days dosing at 24-29 grams per day was successful in curing
malaria (recurrence rate not given). Based on a content of 0.5% artemisinin in the herb, these
amounts provided about 120-145 mg of the compound, much less than used in the recent trials of
the isolated compound or its synthetic derivatives. There may be a group of active compounds in
the herb, leading to successful treatment in the dosage range cited; however, recurrence rates may
be high.
Presumably, when used in the same amounts that treat malaria, ching-hao can be used
prophylactically when traveling in areas with Plasmodium-carrying mosquitoes. If a transfer of the
infectious agent occurs via mosquito bite, the daily treatment should eliminate it, without any
symptoms appearing. Commonly, the dried, hot water extract is used by travelers, with a dose of 6
grams per day (equivalent, roughly, to 24 grams of herb in decoction). Since treatment time for a
case of malaria is just 3-5 days, prophylactic therapy would continue for a few days after leaving an
infested area in an attempt to assure clearance of any parasites picked up at the end of the visit.
There is no data on the safety of such prophylactic therapy over an extended period of use (e.g.,
several months).
8
With its pro-oxidant effects, the high doses of ching-hao used in malarial treatments can only
be recommended for about 3-6 months, a typical duration for administering ching-hao to treat lupus
and other diseases.
Widespread use of ching-hao and its derivatives for prophylaxis (21) or for malaria
monotherapy (18) is not recommended; this could simply contribute to evolution of Plasmodium
strains resistant to this agent. Use of ching-hao during short-term visits by those who are interested
in using Chinese medicine would not be a significant problem in this regard, due to the limited
number of people involved. Current recommended prophylaxis for malaria is mefloquine or
doxycycline. A problem with any potential malaria prophylaxis is compliance with frequent dosing
regimens (23), which may be a drawback for people relying on the herb extracts that are to be
administered twice daily in a bulk form (several grams, about a teaspoon full, each time).
Other Parasites And Infections
In addition to antimalarial effects, artemisinin was found to have promise in treating the parasitic
diseases schistosomiasis and clonorchiasis (common in China and Africa, affecting over 200
million people each year) caused by trematodes (blood flukes). Artemether is now being used for
prophylaxis against schistosomiasis; in combination therapy with praziquantel it is used to treat the
disease (22). Ching-hao is included in effective treatments for leptospirosis, a bacterial disease that
usually infects humans from animal waste contaminating water supplies. It has been shown in
laboratory studies to inhibit Toxoplasma gondii, an organism that mainly affects persons with
compromised immunity, acquired from pets or from eating contaminated meat, and Leishmania
major, a protozoa that infects the macrophages. As described earlier, ching-hao was indicated in
ancient times for topical treatment of skin parasites. In post-revolutionary China, an antiseptic
fumigant was developed using the combination of moxa leaves plus atractylodes (cangzhu). This
combination, burned to produce a cleansing smoke, was reported to serve as protection from viruses
and bacteria in hospitals; both herbs contributed to the action (4). Recent investigations of the
chemical constituents of ching-hao and other Artemisia species have focused on antifungal activity.
An oil produced from the herb after its artemisinin was removed, called huanghua oil (yellow
flower oil; huanghuahao is another name for ching-hao) was shown to be strongly anti-fungal for
all skin fungi tested (26).
Immunological Effects
Ching-hao appears to regulate T-cell responses and antibody production to inhibit autoimmune
reactions (13), with artemisinin being the main active component. Artesunate, which has the same
functions as artemisinin, was evaluated in laboratory animal studies and found to suppress allergic
contact dermatitis and enhance specific suppressor T-cell activity (24).
Clinically, both ching-hao and artemisinin have been used in the treatment of systemic lupus
since 1979, with claimed positive effects in recent trials (12). The dose of artemisinin that has been
9
used clinically for lupus has ranged from 0.2-0.6 grams per day; this corresponds to a dose of chinghao of about 20-30 grams, the same as used to treat malaria. Treatment time is typically about 3
months. Ching-hao has also been applied in treatment of discoid lupus and was deemed successful
(25).
Side Effects And Toxicity
Side effects of ching-hao at normal to high therapeutic doses appear to be rare and mostly involve
gastro-intestinal reactions such as nausea, vomiting, and diarrhea (with or without intestinal
cramping). In a large study in Thailand comparing high-dose artemisinin derivatives (artemether
and artesunate) alone versus in combination with mefloquine, the incidence of adverse effects with
the artemisinin compounds was reported to be 34% for loss of appetite, 16% for nausea, 15% for
dizziness, and 11% for vomiting; mefloquine greatly increased the incidence of side effects,
doubling the rate (20). In a clinical trial comparing artesunate injection with chloroquine and with
the combination of quinine and resorcin, no adverse effects of artesunate were reported, while
dizziness was a common complaint with the drug therapies (35). Animal studies with high-dose
administration of artemisinin had revealed neurological damage, which was initially worrisome, but
this appears to be highly species specific and does not affect humans in the dosage range normally
used (21). Very high doses of the isolated artemisinin caused liver inflammation in animals and in
humans; the human dosage causing this reaction was 10 times the therapeutic dose, given for 3 days
(34). Published reports thus far agree that ching-hao, artemisinin, and its derivatives have low
toxicity.
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Figure 1: Artemesia annua.
Figure 2: Artemesia ketone.
Figure 3: artemisinin.
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