According to the theory and practice of traditional Chinese medicine, yak penis is not only a nutritious food rich in protein, fat, steroid hormones, vitamins C and A, and inorganic calcium, phosphorus and iron, but also can promote the development of male genitalia and maintain its normal function because it contains natural steroid hormones such as testosterone. It is also an excellent diet book for middle-aged and elderly men to tonify kidney, strengthen yang and enhance sexual function.