It is also used for spermatorrhea, frequent urination, and leukorrhea. Wild yam root has been used for hundreds of years to treat rheumatism and arthritis-like ailments. Most species of yams contain large amounts of plant steroids, primarily diosgenin, a saponin precursor in the synthesis of progesterone. Without the yams, the industrial complex would not be able to meet the worldwide demand for synthetic corticosteroids. But with them, scientists can derive animal or human steroids in a fairly straightforward multi step process.
Wild yams are the only really good source of plant steroids for such purposes.
Diosgenin provides about 50 percent of the raw material for steroid synthesis. It must be emphasized that there is not an equivalency between diosgenin and human steroids. It takes many synthetic steps to get from one to the other. If yam has steroidal effects on the body, it is not because it contains steroidal hormones, but because the steroidal precursors have similar effects. The body does not recognize them or mistake them for its own hormones, but uses them in a similar manner.