Yi Yi Ren (薏苡仁) — Job’s Tears Seed | TCM Dampness-Draining Herb Guide

At a Glance

Herb: Yi Yi Ren
Chinese name: 薏苡仁 (Yì Yǐ Rén)
Latin name: Coix lacryma-jobi L. var. ma-yuen (Roman.) Stapf
Nature: Cool
Taste: Sweet / Bland
Meridian: Spleen / Stomach / Lung
Category: Herbs that Drain Dampness
Introduction: Yi Yi Ren (薏苡仁), Job’s tears seed (Coix lacryma-jobi var. ma-yuen), is a gentle yet versatile herb classified across both the 利水渗湿药 (water-draining) and 补气药 (qi-tonifying) categories — reflecting its dual role of draining dampness while simultaneously strengthening the spleen. As both a medicinal herb and a staple food (药食同源), it can be taken daily without side effects. Entering the Lung, Spleen, and Kidney channels, its mild nature makes it suitable for all ages and constitutions. Modern research has identified coixenolide and coixol as its primary anti-tumor and anti-inflammatory compounds, generating significant oncology interest.

Drains dampness and promotes urination (利水渗湿): treats edema, dysuria, and urinary stones.
Strengthens the spleen and stops diarrhea (健脾止泻): addresses spleen deficiency with loose stools and digestive weakness — especially damp-type diarrhea.
Clears heat and expels pus (清热排脓): treats lung and intestinal abscess, skin infections.
Dispels wind-damp and relieves bi syndrome (祛风湿除痹): eases joint pain and heaviness from cold-damp or damp-heat bi syndrome.
Anti-tumor (抗肿瘤): coixenolide has demonstrated anti-proliferative activity in various cancer cell lines; used as adjunctive cancer support.

Spleen deficiency with damp: loose stools, fatigue, poor appetite, abdominal bloating — classic with 白术, 茯苓, 党参 (参苓白术散).
Edema and dysuria: generalized or lower-body edema from spleen-kidney deficiency.
Lung abscess: combines with 苇茎, 桃仁, 冬瓜子 (苇茎汤) for purulent sputum.
Intestinal abscess: early appendicitis pattern with heat and pus formation.
Wind-damp bi syndrome: joint aching and heaviness, especially in damp climates.
Skin disorders: warts (扁平疣), eczema, acne — both internal and topical use.
Cancer support: coixenolide injection (康莱特) used adjunctively in lung and gastric cancer.

Pregnancy: use cautiously in large doses — may stimulate uterine contractions.
Yin deficiency / dry constitution: may further dry fluids with prolonged high-dose use.
Constipation: avoid if bowels are already dry — mild drying and draining nature.
Standard dose: 9–30g in decoction; as food, 30–60g daily is safe.
Preparation: raw Yi Yi Ren (生薏苡仁) drains dampness and clears heat; dry-fried Yi Yi Ren (炒薏苡仁) warms and strengthens the spleen — better for diarrhea.

参苓白术散 (Shen Ling Bai Zhu San): Yi Yi Ren + Ren Shen + Fu Ling + Bai Zhu — spleen qi deficiency with dampness; the classic formula for digestive weakness and diarrhea.
苇茎汤 (Wei Jing Tang): Yi Yi Ren + Wei Jing + Tao Ren + Dong Gua Zi — lung abscess with heat, pus, and blood-tinged sputum.
薏苡附子散 (Yi Yi Fu Zi San): Yi Yi Ren + Fu Zi — chest bi syndrome with cold-damp.
麻黄杏仁薏苡甘草汤 (Ma Huang Xing Ren Yi Yi Gan Cao Tang): wind-damp bi syndrome with fever and joint pain.

For spleen deficiency with diarrhea and edema: combine with Bai Zhu, Fu Ling, Ren Shen (Shen Ling Bai Zhu San).
For lung abscess with purulent sputum: combine with Wei Jing, Dong Gua Ren, Tao Ren (Wei Jing Tang).
For intestinal abscess: combine with Fu Zi, Bai Jiang Cao (Yi Yi Fu Zi Bai Jiang San).
For bi syndrome (damp painful obstruction): combine with Du Huo, Wei Ling Xian, Fang Ji.
For damp-heat causing flaccidity of lower limbs: combine with Cang Zhu, Huang Bai.
For warts and skin growths: combine with Ban Lan Gen, Ma Chi Xian.
For cancer adjunct therapy: use alone or combine with Ban Zhi Lian, Bai Hua She She Cao.

coixenolide
- Antitumor: inhibits proliferation of cancer cell lines (lung, liver, colon)
polysaccharides
- Immunomodulatory: enhance macrophage and NK cell activity
coixan
- Hypoglycemic: lowers blood glucose via insulin-sensitizing mechanisms
Anti-inflammatory
- inhibits COX-2 and 5-LOX pathways
Diuretic
- increases urine output through renal tubular effects
coixol
- Antispasmodic: relaxes skeletal muscle and reduces convulsions

Shen Nong Ben Cao Jing (《神农本草经》): ‘Governs sinew urgency and contracture, inability to flex and extend, wind-damp impediment, and descends qi; long-term use lightens the body and benefits qi.’
Ben Cao Gang Mu (《本草纲目》): ‘Strengthens the Spleen and benefits the Stomach, supplements the Lung and clears heat, expels wind and overcomes dampness; cooked into rice it treats cold qi; decocted and drunk it promotes urination and treats heat strangury.’
Ben Cao Jing Shu (《本草经疏》): ‘Coix Seed: its nature is drying and can eliminate dampness; its sweet flavor can enter and supplement the Spleen; combined with blandness it can percolate and drain — hence it governs sinew urgency and contracture.’
Ben Cao Zheng (《本草正》): ‘Coix Seed is sweet and bland in flavor, slightly cooling in qi, slightly descending and percolating in nature — hence it can eliminate dampness and promote water.’