Epimedium P.E.(Horny Goat Weed P.E.) shorthorned Epimedium Herb extracts. Horny Goat Weed is a traditional botanical medicine used in China and Japan. Although this herb (which also goes by the names Yin Yang Huo, Inyokaku, and Herba Epimedii) has a history of traditional use for disorders of the kidneys, joints, liver, back and knees, its principle use is as an aphrodisiac. According to one herbal author, Horny Goat Weed has testosterone-like effects. It stimulates sexual activity in both men and women, increases sperm production, stimulates the sensory nerves, and increases sexual desire.