Many medicinal plants are designed to improve health but their mechanism of action remains not clear. Among these plants, garlic (Allium sativum) has attracted particular attention of modern medicine because of its widespread use for the prevention and treatment of some human diseases such as cardiovascular diseases and cancer. However, the impact of garlic on the male reproductive system has not been clearly defined. Some studies have reported that garlic improves male sexual function and has beneficial effect in the recovery of testicular functions. However, other authors have shown that this plant impairs testicular functions (such as inhibition of testosterone production) and has spermicidal effect on spermatozoa. In this review, we attempt to clarify the current ambiguity regarding the effects of garlic and its preparations on the male reproductive system.