Earthworms in Traditional Chinese Medicine (Oligochaea: Lumbricidae, Megascolecidae)

The earthworm, (sic) (gin yin) was first documented in the Divine Farmer's Materia Medica Classic ((sic)) around 200 B.C - 200 A.D. The 365 drugs in this book were classified into three groups: up, middle, and low. The 120 drugs in the up group are regarded as nontoxic and benefit qi (able to strength the vital body energy), so they can be taken regularly. The 120 drugs in the middle group are toxic or non-toxic, and used for treating diseases and supplementing deficiency. The drugs in the low group are toxic, and can eliminate "evil" (anything which causes illness) and should not be taken for a long period of time (Toxic implies the drug has strong medicinal effect and could have side effects so should be used properly and cautiously). The earthworm belongs to the low group. But in later medical literature, the earthworm is considered as non-toxic (Compendium of Materia Medica (sic), 1552-1593).