Garlic (Allium sativum)

Overview Garlic’s current principal medicinal uses are to prevent and treat cardiovascular disease by lowering blood pressure and cholesterol, as an antimicrobial, and as a preventive agent for cancer. The active constituents are several complex sulfur-containing compounds that are rapidly absorbed, transformed and metabolized. Pooled data from numerous randomized trials suggest that garlic lowers total cholesterol concentrations by approximately 10% and favorably alters HDL/LDL ratios. Randomized trials also support garlic’s effectiveness as a mild antihypertensive which lowers blood pressure by 5-7%. Garlic also inhibits platelet aggregation and enhances fibrinolytic activity, reducing clots on damaged endothelium. In vitro data suggest antiviral and antibacterial effects, but these have not been evaluated in controlled trials in humans. Epidemiologic data, in vitro studies and animal data suggest that garlic may help prevent some solid tumors, but no randomized trials have evaluated its effectiveness as a therapeutic agent in oncology. There are no studies evaluating its effectiveness or safety in treating children or pregnant or nursing women. Garlic is safe when eaten as food, though in some sensitive persons, it can cause gastrointestinal irritation, and of course, halitosis. Prolonged topical use has been associated with moderate burns.