Mexican yam (Dioscorea mexicana): names, traditional uses, diosgenin, preparation, synergies, contraindications and the myth of natural progesterone.

Wild yam (Dioscorea villosa): traditional uses, tea and cream preparation, and contraindications in pregnancy and hormone-sensitive cancer.

Dioscorea hispida, the Asiatic bitter yam: taxonomy, morphology, habitat, phenology, phytochemistry and the documented toxicity of its huge starchy tubers.