By Tony Harrison
Tony Harrison is the joint founder of the Chinese Herb Garden and the current garden co-ordinator for the Register of Chinese Herbal Medicine (RCHM); this is the first in a series of plant spotlights.
If you go into the Chinese Herb Garden in late summer you may find the seeds of Coix lacryma-jobi, otherwise known as jobs tears. There are several species and variations of Coix lacryma-jobi species. Coix lacryma-jobi var. lacryma-jobi was introduced into the Middle East from Asia and it gets this name for the use of the hard white ripe seeds which are threaded into rosary beads for Muslim devotional prayer.
Different varieties of the plant are cultivated throughout Asia where it used for ornamentation and as a food. The miim festival of the Zomi peoples of Myanmar is named after Coix where it is given as a tribute to parting souls. Perhaps this association may be behind its use in Borneo by the Kayan people as ornaments in their war dress.
Other common names for this plant include Chinese pearl barley or Alday millet, but it is neither a barley or a millet, although also a member of the grass family Poaceae.
Coix lacryma-jobi grows at higher altitudes than rice and does not need polishing like rice which removes nutrients. It is composed of around 58% starch which is free of gluten. In addition it contains 8 amino acids and vitamin E. This makes it an important food crop in mountain regions where rice will not grow and also for use in a gluten free diet.
The taste is slightly sweet and it has a slight cooling effect. The seeds are often ground into flour and used in desserts in Cambodia and as a common ingredient in the traditional moon cakes used in the mid autumn festival in China.
The seed is known as yi yi ren in Traditional Chinese Medicine (TCM). It derives from a cultivated variety known as Coix lacryma-jobi var. ma-yuen. This variety has a smaller seed which also does not have a hard outer shell.
Yi yi ren is used in TCM as a gentle digestive tonic which also removes damp heat.
In this instance ‘damp’ equates to a build up of fluids in the body. When this occurs in the intestines it can reduce its function and impair absorption. Candida albicans yeast will take hold and dominate in the bowel flora under these cold damp conditions. When damp is combined with heat then inflammation can become a feature.
Research has shown that yi yi ren does contain a small proportion of phenolic flavenoids with anti inflammatory effect, but its main action may be more related to a tonic effect on the gut micro biome. Research has found that it has a positive effect on the gut bacteria including an increase in lactotobacillus, coprococcus, and akkermansia. (1)
It is easy to buy Coix lacryma-jobi seed as a food supplement or as a culinary ingredient. If you are a keen gardener you can also order the seed for cultivation. The variety you will see in the garden is the larger hard shell Coix lacryma-jobi var. lacryma jobi.
Its natural habitat is damp ground in tropical and subtropical regions. It does grow outside in the UK in the full sun in well drained but damp soil. It is not especially cold hardy so we tend to grow it annually from seed, although it will overwinter in a glasshouse.
You will need to sprout the seed early indoors to get a long enough growing season to set seed.
References:
1: Peihan Zhao et al : Journal of Inflammation Research 18 :2025
Exploring the potential of Coix seed to mitigate gut inflammation via microbiota and metabolite modulation.
