Part 2 of 2: Soybean

In an earlier post, we introduced the soybean and some of its uses in Chinese medicine. Today, we look at traditional versus modern uses as well as some classic home remedies.

The recorded use of black soybean in Chinese medicine preceded that of yellow soybean. The former dates back at least 2,000 years, being listed in the Shennong Herbal, while the latter dates back to only around A.D. 1330. Consequently, there is much more documentation on the medicinal uses of black soybean and its derived products than on those of yellow soybean. Black soybean, black soybean skin (seedcoat), fermented black beans, yellow soybean, and yellow bean sprout, as well as other, less common forms of soybean, are all used medicinally.

Black soybean skin is prepared in the following manner: The beans are soaked in clean water until they germinate, or until the skins separate easily. The skins are then removed and sun-dried. They are kept in a dry place, ready for use.

The first recorded medicinal use of black soybean skin dates back to the middle of the 8th centruy, during the Tang Dynasty. It is said to nourish the blood, clear one's vision, and drive away disease-causing factors. It is used in treating excessive sweating, night sweat, dizziness, headache, and rheumatoid arthritis and is usually taken in the form of a decoction, with a usual daily dose of 9 to 16 g. (0.3 to 0.6 oz.).

There are two kinds of fermented black soybeans (dou chi in Chinese) - unsalted and salted. Although the only difference between the two is the added salt, the former is more commonly used in Chinese medicine. Fermented black beans are prepared by a complicated process that involves soaking black soybeans in a water extract of white mulberry leaves and a wormwood herb (e.g., Artemisia annua), followed by steam-cooking and spontaneous fermentation. Other herbs such as licorice and Ephedra sinica (ma huang, in which ephedrine was first discovered) are also used.

The first recorded use of fermented black beans in Chinese medicine dates back to the early 6th century, during the Liang Dynasty. It is considered bitter tasting and is said to be good for treating illnesses that affect the lungs and the digestive system. It is used in treating colds, fevers, typhoid, headache, and discomforts in the chest. For these illnesses, it is usually taken internally as a decoction, with a daily dose of 6 to 12 g. (0.2 to 0.4 oz.).

Yellow soybean is considered to have the same medicinal nature to black soybean and is used in treating similar conditions.

Yellow bean sprouts are prepared by keeping yellow soybeans under wet and warm conditions until they germinate and the sprouts reach about two inches in length. Although practically unknown to most Westerners, yellow bean sprouts are a common vegetable in the Chinese diet. They taste different from mung-bean sprouts, the latter being the bean sprout most Westerners find in Chinese dishes.

The use of soybean in the treatment of long-term leg ulcers was described in 1951 in a medical journal from northeastern China. According to this report, yellow soybeans were washed with warm water and partially cooked in water. After being stirred to separate and remove the skins, the beans were mashed to form a paste to which preservative was added. The ulcer was wiped clean and the bean paste was placed on a piece of thick gauze and applied directly to the ulcer. The medication was changed once a day. This treatment was used on four patients who had had leg ulcers for one-and-a-half to 12 years. All were healed after this treatment. This application was based on a traditional remedy.

An application of yellow bean sprout for treating the common wart was reported in 1963 in a regional medical journal from southeastern China. Patients under treatment were fed only plain, water-boiled yellow bean sprouts, without salt or other seasoning, three times a day. No other foods were allowed until the fourth day, when patients resumed their normal diet. All four patients treated were cured and their warts did not reappear.

There are many recorded remedies using soybean and, as in keeping with traditional practice, most of them contain more than one herb. Nevertheless, there are some remedies that call for soybean alone. Thus, for treating hot-water or fire burns and erysipelas (an acute bacterial disease marked by fever and severe skin inflammation), black beans are cooked in water and the concentrated liquid is applied directly to the affected areas of the skin. Wounds are said to heal with no scars. To treat poisoning due to drugs such as croton and arsenic, boiled black-soybean juice is taken internally; sometimes, the beans are boiled with licorice to enhance their detoxifying effects. Incidentally, croton oil was an official drug (as a purgative) in the United States up to 1947, when it was discarded as being too dangerous. Nevertheless, croton seed and croton oil are still used in Chinese medicine as they have been for thousands of years (both are described in the Shennong Herbal) for treating numerous disorders.

For treating a common condition characterized by dry mouth, sore throat, dry cough, and constipation, the following common home remedy is used: About four pounds of yellow bean sprouts are cooked in plenty of water for four to five hours and the liquid is taken as a drink.

Availability: Yellow soybeans are available in health food stores, groceries, Chinese groceries, and some supermarkets. Black soybeans, fermented black beans, and yellow soybean sprouts are available in Chinese groceries.

This information is excerpted from Dr. Albert Leung’s book, Chinese Healing Foods and Herbs. This publication includes further information and home remedies using soybean as well as over 45 other herbs. Learn more about soybean and read further about Dr. Leung and his writings! Visit http://www.earthpower.com/.