By Eric Brand

Yi Yi Ren is a very common medicinal with broad applications in Chinese medicine.  It was used in the early Han dynasty over 2000 years ago, and appears in classical formulas from texts such as the Shang Han Lun, which featured many clinical combinations that remain in popular use.  Like Bai Zhu, Gan Cao, and Huang Qi, Yi Yi Ren is commonly used in both raw and stir-fried forms, with slightly different indications for each form.  Stir-frying with bran (about 10 kg of bran per 100 kg of Yi Yi Ren) is common, as is simple dry stir-frying.

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Yi Yi Ren is a sweet, supplementing, bland, and percolating medicinal that is similar in nature to Fu Ling (Poria). It is most suitable for spleen vacuity with damp stagnation. To treat water swelling and abdominal distention from spleen vacuity with exuberant dampness, manifesting in reduced eating and diarrhea, leg qi (beriberi), or puffy swelling, combine it with Fu Ling (Poria), Bai Zhu (Atractylodis Macrocephalae Rhizoma), and Huang Qi (Astragali Radix). For diarrhea and spleen vacuity, it is commonly used within the formula Shen Ling Bai Zhu San. The stir-fried form is neutral in nature and is best to fortify the spleen and check diarrhea.

Yi Yi Ren is also an important medicinal for impediment (bi) conditions.  It percolates dampness, soothes the sinews, and relaxes tension. For enduring wind-damp impediment with hypertonicity of the sinews and water swelling, it can be made into a congee that can be taken as food.   The raw form is preferred for impediment conditions, and the raw form also has a stronger effect on disinhibiting urination.  The raw form has a cooling nature so it is particularly suited to damp-heat conditions. For damp-heat conditions, Yi Yi Ren is often used with Huang Bai (Phellodendri Cortex), Cang Zhu (Atractylodis Rhizoma), and Niu Xi (Achyranthis Bidentatae Radix), as in the formula Si Miao San (Four Miracle Powder).

Additionally, Yi Yi Ren clears heat and expels pus, and is used for lung and intestinal welling-abscesses.  For this application, the raw form is preferred.  To treat chest pain from welling-abscesses in the lung with coughing of pus and phlegm, combine it with Dong Gua Zi (Benincasae Semen) and Tao Ren (Persicae Semen). For intestinal welling-abscesses, use it with Fu Zi (Aconiti Radix Lateralis Praeparata), Bai Jiang Cao (Patriniae Herba), and Mu Dan Pi (Moutan Cortex).

Yi Yi Ren, by its ability to clear damp-heat and expel pus, is also often used for acne and to generally enhance the treatment of skin conditions. For this purpose it can be liberally added to soups and congees.  In Japanese Kampo, it is also added to Gui Zhi Fu Ling Wan to make an empirical formula for stubborn cases of acne.

Note that two forms of Yi Yi Ren are sold in Chinese pharmacies: large seeds and small seeds. The larger one is coix, the medicinal used in Chinese medicine.  The smaller one is pearled barley. Coix is more potent for medicinal use but pearled barley has a better taste as a food.