Job's Tears (Coix Seed)

Coix Seed (yi yi ren, 薏苡仁), also known as Semen Coicis, Job’s Tears and Chinese Pearl Barley, comes from the Coix plant (Coix Lacryma Jobi). This plant is grown in the Fujian, Hebei and Liaoning provinces in China. It has oval-shaped or egg-shaped seeds that have a yellow, brown, white or purple outer surface. These ancient grains have more protein than any other cereal grains, and they are environmentally friendly because they do not require a lot of water to prosper.

Since 100 AD, Job’s Tears have been recommended for the treatment of pain and stiffness in limbs. The use of these seeds in medicine then spread to Japan when the Chinese herb system was brought to Japan in the 16th and 17th centuries. In Japan, Job’s Tears are revered as the secret to timeless beauty. They are used in many Japanese supplements to promote skin vitality. These seeds are also sometimes used as ornamental beads.  

Job’s Tears are harvested in the fall when the Coix plant ripens and are dried under the sun. They are usually used unprocessed or stir-baked till their outer shell becomes yellowish in colour.

In Traditional Chinese Medicine (TCM), Job’s Tears falls under the category of ‘Herbs that drain Dampness’. Such herbs are typically diuretics, as they can promote the production of urine to remove accumulated Dampness in the body, which may cause edema, impaired movement of lower limbs, impaired digestion and impaired respiratory system if left unchecked.

Cool in nature, Job’s Tears can help individuals who have too much Heat in their body, such as those experiencing a Yang Excess or a Yin Deficiency, to restore a harmonious yin-yang balance. Sweet in taste, the herb can slow down acute reactions, detoxify the body, and has a tonic effect on the body by replenishing qi and blood. In particular, the herb targets the Lungs, the Spleen and the stomach.

Traditional Chinese Medicine (TCM) shows that Job’s Tears have the following health benefits.

Job’s Tears can induce diuresis to drain Dampness from the body. It helps to relieve symptoms caused by the accumulation of Dampness in the body, such as oedema, dysuria, abdominal fullness and the downward flow of damp turbidity to the foot. Also, Job’s Tears can invigorate the Spleen. The herb can thus check diarrhoea caused by Spleen Deficiency. 

Job’s Tears can clear Heat, and is used to address Heat arthralgia and urolithic stranguria. By removing Dampness, soothing muscles and relaxing spasms, the herb can address arthragia manifested as pain and spasm of tendons. Other symptoms that this herb may be able to treat include rheumatoid arthritis, appendicitis and colitis.

In addition, Job’s Tears can clear Heat in the Lungs and drain Dampness from the intestines and stomach to expel pus and cure abscess. For example, the herb can be used to treat pulmonary abscess manifested as chest pain and cough with purulent phlegm with unpleasant odor.

Modern studies have discovered many Coix Seed benefits for skin. Coix Seeds contain proteolytic enzymes that help soften the keratin layers of skin, which makes the skin smoother, reduces wrinkles and improves dark spots. The herb’s benefits for skin do not end here, it also contains properties that manage skin problems like acne breakouts, eczema, rosacea, sebum production, warts, skin allergies such as heat rashes, as well as skin sensitivity. Regular consumption of Job’s Tears can reduce the appearance of hyperpigmentation and moisturise the skin. In Japan, a highly concentrated extract of Coix Seeds is promoted as a support for beautiful skin, hair and nails.

Job’s Tears are also used for weight loss by removing water retention. It is frequently prescribed to patients experiencing swelling in the legs or gastrointestinal problems such as diarrhoea, poor digestion and abdominal bloating. Containing high levels of essential fatty acids, Job’s Tears are also used to relieve inflammation and combat viral infections. In addition, the herb is found to possibly help reduce cholesterol levels, lower the risk of cancer, treat endocrine disorders, and address osteoporosis.

The recommended daily dosage of Job’s Tears is 9 – 30g. The herb can be combined with water to make a decoction or ground into powder. To clear Heat and drain Dampness, Job’s Tears are usually used unprocessed. On the other hand, to invigorate the Spleen and arrest diarrhea, Job’s Tears are usually stir-baked.

Both unprocessed and stir-fried Job’s Tears can be found at some Asian markets. While Job’s Tears decoctions and powders are harder to find, they are still often available in some markets and specialty stores.

Other than being used in herbal formulas and culinary dishes such as cold desserts and boiled soups, Job’s Tears can also be applied on the skin directly. In fact, you can find Coix Seed Extract in many skin and health products around the world.

Job’s Tears should not be used by individuals who are pregnant, on their menstrual period, or experiencing dehydration. Examples of dehydration symptoms include dry throat, constipation, excessive perspiration and excessive urination. Individuals with spermatorrhea or polyuria should use this herb with caution too.

In addition, as Job’s Tears may decrease blood sugar levels, it is best to not consume this herb if you are on diabetes medication.

Here is a summary for Job’s Tears (Coix Seed):

• Herb name (Chinese): 薏苡仁
• Herb name (Pin Yin): yì yǐ rén
• Herb name (English): Coix Seed
• Herb name (Botanical): Semen Coicis
• Origin of species: Coix lacryma-jobi L. var. mayuen (Roman.) Stapf
• Part(s) of herb used: Kernel
• Geo-specific habitat(s): Fujian, Hebei, Liaoning
• Taste(s) & Properties: Sweet, bland; Cool; Administrates the Spleen, Stomach and Lung meridians
• Actions: Eases water retention in the body; Nourishes the Spleen and Stomach Systems; Relieves rheumatic pain; Induces drainage of pus and relieves symptoms of lung or appendiceal abscesses; Aids in detoxification and relieves conditions of nodules and swellings

Arora, R. K. (1977). Job’s-tears (Coix lacryma-jobi)—a minor food and fodder crop of northeastern India. Economic Botany, 31(3), 358-366. [Accessed on 9th December 2022]

Kwak, C. S., Lim, S. J., & Kim, S. A. (2004). Antioxidative and antimutagenic effects of Korean buckwheat, sorghum, millet and Job’s tears. Journal of The Korean Society of Food Science and Nutrition. [Accessed on 9th December 2022]

Suzuki, Y., & Konaya, Y. (2021). Coix seed may affect human immune function. Natural Product Communications, 16(10), 1934578X211048642. [Accessed on 9th December 2022]

Zhu, F. (2017). Coix: Chemical composition and health effects. Trends in food science & technology, 61, 160-175. [Accessed on 9th December 2022]