Yi yi ren, also known as coix seeds or Job's tears, comes from Fujian, Hebei and Liaoning provinces in China. It usually has an oval shape and a white surface. It tastes sweet and has cooling properties. In traditional Chinese medicine, the seeds treat conditions that relate to the spleen, stomach, lungs, skin, liver and large intestine.
The yi yi ren plant looks like tall grass that reaches about 3 to 7 feet (1 to 2 meters) in height. In the fall, the egg-shaped seeds ripen and are harvested. The seeds are then peeled to remove the shell and sometimes also stir-baked or stir-fried until the surface turns yellow. Asian markets often sell the raw and cooked seeds, but usually only specialty stores sell the tea and powder forms.
Since about 100 A.D., coix seeds have been recommended for the treatment of pain and stiffness in limbs. The use of the seeds in medicine spread to Japan during the transfer of the Chinese herb system to Japan in the 16th and 17th centuries. When Chinese medicine entered the United States market in the 1980s, yi yi ren was an ingredient in one of the first Chinese herbal formulas.
Yi yi ren promotes the health of various internal organs, especially the spleen and the lungs. It removes heat, reduces swelling, relieves joint pain, clears heat, eliminates phlegm, drains pus and triggers diuresis. Chinese medicine practitioners also use it to treat diarrhea, rheumatism, arthritis and cancer. The ingredients in the seeds also are said to treat skin diseases and improve the skin, hair and nails. One study found yi yi ren to improve cytotoxic activity, which could help the body fight viral infections.
Typically, a sick person takes 0.35 ounces to 1 ounce (10 to 30 g) of yi yi ren per day, depending on the condition being treated. The seeds have only moderate strength, so persons suffering from severe diseases often take 1 to 2 ounces (30 to 60 g) over a long period of time. The seeds usually are ground into powder or boiled in water using a special decoction technique. Another technique involves combining the seeds with rice to eat in a meal. Yi yi ren has no known side effects, but any person who intends to use it as a supplement or medicine should consult a qualified health care practitioner.