A traditional medicinal herb in China, horny goat weed (botanical name: epimedium) has an ancient use history. Chinese medicine employs it for numerous ailments, including hay fever, osteoporosis, and, yes, erectile dysfunction. Clinically, epimedium has had some circulatory benefits in humans, as well as the potential to inhibit PDE 5 similarly to prescription tadalafil. However, research in humans is still limited and far from conclusive.