THE MEDICINAL USE OF SNAKES IN CHINA
Among the earliest recorded use of snakes in Chinese medicine was the application of sloughed snake skin, described in the Shen Nong Ben Cao Jing (ca. 100 A.D.) It was originally applied in the treatment of superficial diseases, including skin eruptions, eye infections or opacities, sore throat, and hemorrhoids. The use of snake gallbladder is first recorded in Ming Yi Bie Lu (Transactions of Famous Physicians; compiled by Tao Hongjing, and written around 520 A.D.), which was an update of the Shen Nong herbal with double the number of ingredients. In addition to the gallbladder, the skin (fanpi) and the meat of a pit viper (Agkistrodon halys; fanshe), were also described. They were used to treat skin diseases, pain, and intestinal hemorrhage.
Other species of snakes were also mentioned in the medical literature: zaocys, the non-toxic black-striped snake (wushaoshe) was described in Yao Xing Ben Cao by Zhen Quan (ca. 600 A.D.), and the toxic white-patterned pit viper, agkistrodon (A. acutus, baihuashe or qishe) was described in Kai Bao Ben Cao by Mai Zhi in 973 A.D. Among the earliest records of using snakes for food come from the Tang Dynasty (618–907 A.D.), including the meat of pythons and pit vipers. It is likely that the more widespread use of snakes for food and medicine during the Tang period derived from the Indian culture. The Tang Dynasty period is especially known for its willingness to accept foreign influences, including those from India and Arabia (in ancient Egypt and Mesopotamia, many animal substances were used as medicine).
There are at least three features of snakes that capture the attention of traditional healers: they have an incredible flexibility and speed, they shed their skin, and certain snakes are extremely poisonous when they bite.
The flexibility of snakes has suggested that they might be helpful in the treatment of stiffness, for example, arthritis. Two types of snakes, agkistrodon and zaocys, are currently used in several traditional and patent prescriptions for arthritis, and they are sometimes soaked in alcohol to make an extract for stiff joints. The speed with which some snakes move indicated to traditional observers that, as medicines, their substance can move quickly around the body. Snakes are said to treat “wind” syndromes, which likewise tend to move around quickly. However, people are also cautioned not to consume snake wine when exposed to potentially pathologic wind, as the rapid movement of the snake medicine may aid the initial penetration of wind.
The fact that snakes shed their skin has suggested that they have a regenerative quality for treating chronic skin problems. As a result, snake skin and whole snake are used in the treatment of skin diseases. This application is similar to the use of sloughed cicada skin for treating skin ailments. Acne, carbuncles, itching skin, and psoriasis are examples of conditions that may respond to snake skin. Snake skin is also considered useful in reducing clouding (nebula) of the cornea, the “skin” of the eyes.
Poisonous animals often cause paralysis when they bite and this is due to the presence of neurotoxins. They are then used medically by oral administration (which greatly reduces the toxicity) for the treatment of convulsions (by inhibiting intense muscle contractions). Also, some forms of paralysis are “tonic” in nature, that is, due to overcontraction of muscles, and in such cases the nerve toxins can overcome paralysis. Agkistrodon (but not zaocys) is a poisonous snake used for epilepsy and paralysis. Scorpions and millipedes (scolopendra) are used similarly. Anti-convulsive activity is also ascribed to snake skin and cicada skin.
In the Ben Cao Gang Mu (1590 A.D.) by Li Shizhen, it was said that “Agkistrodon penetrates the bone to expel the pathogenic wind and alleviate convulsion and is the essential material for wind arthralgia, convulsion, scabies and malignant scabies—because it travels everywhere, outward to the skin and inward to the viscera.” It was noted in Illustrated Materia Medica that “Agkistrodon has a quicker effect in treating wind syndrome than that of other snakes.” Several records in Chinese medical books indicate that snake slough is useful for malignant sores, such as mammary abscess and tumor, boils, carbuncles, and furuncles. The slough is usually roasted and then used both internally and topically.
Snake bile has long been valued as a tonic, characterized as such by its sweet aftertaste. It is used to make a special health drink at snake restaurants (which are today still found in southern China, Hong Kong, and Taiwan). The bile of a snake to be eaten is mixed with some rice wine and consumed before the meal as an invigorating beverage and appetite stimulant. In the treatment of diseases, snake bile is used for whooping cough, rheumatic pain, high fever, infantile convulsion, hemiplegia, hemorrhoids, gum bleeding, and skin infections.
One of the best known remedies using snake bile is San She Dan Chuan Bei Mu, or the mixture of three snake gallbladders plus the herb fritillaria (F. thunbergii). It is made as a powder or a liquid; only the powder is imported to the West. The three snake gallbladders are usually derived from agkistrodon and zaocys species, but there are numerous substitute species used in the marketplace. In fact, a major active component—the bile acid known as taurocholic acid—was analyzed in the 16 species of snakes now traded commonly and in 8 samples of snake bile and fritillaria liquids. The highest level of this component was in the bile from a species of Naja snake (a cobra), and the lowest was in zaocys; among the cough remedies, the cholic acid concentration varied from .025 to .069 mg/ml, which is nearly a three-fold range. In the Chinese Pharmacopoeia, the official recipe for the mixture is 1 part snake bile added to 6 parts fritillaria powder (dry, and pulverize the mixture); the dosage is just 300–600 mg at a time, 2–3 times per day. The antitussive action of bile from one snake tested, Hydrophis cyanocinctus (a sea snake), is one-ninth that of codeine when assayed in mice (adult human codeine dosage for treating cough is 20–30 mg). Snake bile is collected in spring and summer when the content of solids is highest. Snake gallbladder is sometimes combined with pinellia or citrus to produce an antitussive and phlegm-resolving powder for treatment of acute bronchitis.
The bile from two snakes, Naja naja (Indian cobra) and Ophiophagus hannah (king cobra) show 11 bands in thin layer chromatography (TLC), while the bile from most other snakes show only 8 of those bands, indicating unique medicinal ingredients in the cobra. All the snakes contain cholic acid but not deoxycholic acid or lithocholic acid. In the marketplace, snake gallbladders are sometimes substituted by those of geese, ducks, and chickens. These gallbladders have a different form that can be easily distinguished by those who make the effort to do so; further, the TLC profile of the bile from these substitutes is entirely different from that of the snakes, and the bile from fowl do not produce the sweet aftertaste common to the snake bile.
Snakes are also used in the treatment of cancer. The small agkistrodon is a common ingredient in modern treatments, especially for leukemia. A combination of Agkistrodon halys and Natrix trigrina (water snake), in the form of a powder (3–5 grams per day), is used as an adjunct to herbal decoctions and drugs to treat hepatoma. Snake venom is also sometimes used as medicine; recent research has shown that snake venom may have value in treating cardiovascular diseases. Blood pressure reducing and anticoagulant properties have been identified, and are especially prevalent in the vipers.
Most of the snakes are now raised, but the materials on the market place come from a variety of sources, including those collected in the wild. Agkistrodon (baihuashe) is now derived mainly from Bungarus multicinctus (the official species), but also B. fasciatus (banded krait), Natrix annularis, Enhydris chinensis and E. plubea, and Dinodon rufozonatum. Zaocys is mainly derived from Z. dhumnades, but also from Dinodon rufozonatum, Elaphe carinata, E. rufodosata, and E. taeniura, Natrix annularis and N. stolata, Ptyas korros and P. mucosus. Snake bile is obtained from sources such as Naja naja atra, Bungarus fasciatus, Elaphe radiata, Ptyas korros, and Zaocys dhumnades.
Because there are some snakes that are now endangered species, and because the snakes or their isolated bladders are not easily identified by officials, the U.S. Wildlife Department has restricted import of all snake medicinal materials unless the shipment is accompanied by a suitable certificate indicating the origins of the snakes. Further, the FDA has restricted import of many liquid preparations, including the liquid forms of snake bile.
Unfortunately, the use of
snake materials may be virtually eliminated in the West, because most Chinese
suppliers are not otherwise compelled to spend time and effort certifying the
origins of the materials. The U.S.
market for snake materials is very small.
In fact, aside from Chinese doctors working in the U.S. and prescribing
the materials directly, ITM has been one of the only producers of formulas that
utilize snake materials. These formulas
include a treatment for gallbladder disorders (San She Dan Tablets), for skin itching (Zaocys Tablets), for
arthralgia and hypertension (Clerodendron Tablets), and for recovery from
surgery (Recovery Pills); all together, only about 60 pounds of snake and 40
pounds of snake gallbladder are needed for a one year supply of these
formulas. China’s total production of
snake for medicine is measured in tons.
One means of helping to preserve snakes is to use the snake materials in powder form rather than using them in decoctions. The powdered snake is usually recommended in dosages that are about 1/3 to 1/6 that for decoction of the same materials (the Pharmacopoeia of China gives a dosage of agkistrodon for decoction at 3–9 grams, but for powder to be swallowed, only 1–1.5 grams), probably because decoction poorly extracts some active components and damages others. Cold alcohol extraction is considered acceptable and allows use of small doses as well.
May 1997