Medicinal plants such as thyme, onion, blackseed, lemon balm and nettle are intensively used in traditional medicine, today. Garlic is among the most important of these plants. For this purpose, garlic has been extensively used worldwide for centuries, especially in the Far East. Garlic is reported to be a wonderful medicinal plant owing to its preventive characteristics in cardiovascular diseases, regulating blood pressure, lowering blood sugar and cholesterol levels, effective against bacterial, viral, fungal and parasitic infections, enhancing the immune system and having antitumoral and antioxidant features. Garlic exerts these effects thanks to more than 200 chemicals. It contains sulfur compounds (allicin, alliin and agoene), volatile oils, enzymes (allinase, peroxidase and miracynase), carbohydrates (sucrose and glucose), minerals (selenium), amino acids such as cysteine, glutamine, isoleucine and methionine which help to protect cells from the harms of free radicals, bioflavonoids such as quercetin and cyanidin, allistatin I and allistatin II, and vitamins C, E and A which help to protect us from oxidation agents and free radicals, and other vitamins such as niacin, B1 and B2 and beta-carotene. In this article, the information about the characteristics of garlic, the diseases on which it is effective and its use against parasitic diseases will be given.