Despite its pungent odor and strong flavor, garlic is not poisonous. It's been a staple of cuisines around the world for thousands of years and was even used to prevent gangrene during the first and second World Wars and to fend off the plague in 18th century France. Garlic is still enjoyed today, both as a diet-friendly culinary flavoring and as an herbal supplement. The amount normally used in cooking is safe, but medicinal strengths may interact with certain medications and conditions.
Allicin
According to MedlinePlus, garlic may have a beneficial effect on blood pressure, atherosclerosis and skin infections. The University of Maryland Medical Center says it may be a weapon against the common cold and may help prevent certain cancers. Allicin is the active component in garlic, providing both the medicinal benefits and the characteristic smell. Some supplement manufacturers sell odorless garlic supplements, but MedlinePlus warns that these contain very small amounts of allicin, and some contain none at all. For medicinal purposes, the higher the allicin concentration, the more effective the supplement is likely to be.
Healthy Cooking
Beyond the potential health benefits, garlic is a powerful tool in the healthy cooking arsenal by adding flavor without fat, calories or sodium. Press a clove over a vegetable stir fry, or blend it with tomatoes for a rich soup. Roast a bulb of garlic, then squeeze the pulp from the peel for a spread that replaces high-fat, high-calorie butter. Cut slits in a raw chicken breast, fill them with garlic slivers and roast it for a lean, flavorful entree. By adding flavor with herbs like garlic, you can avoid heavy, high-calorie sauces and dips that can derail your diet.
Dose
The medicinal effects of garlic require higher doses than you would normally eat in food. If you enjoy the taste, the University of Maryland Medical Center recommends eating two to four raw cloves per day. If you prefer the pill form of the supplement, follow the dosing instructions on the package -- generally two tablets up to three times per day. Garlic extracts are usually used at 600 to 1,200 mg per day; a one-to-one fluid extract would be 4 mL daily, and a one-to-five tincture would be 20 mL daily. Follow dosing instructions on the bottle, or ask your doctor for the correct dose.
Caution
The University of Maryland Medical Center says that garlic thins the blood, so don't use it if you are taking blood thinners, protease inhibitors or antiplatelet drugs or are about to have surgery. It may also interact with cyclosporine and medications changed by the liver, and it may reduce the effectiveness of oral contraceptives, according to Medline Plus. MedlinePlus also says that garlic is safe for pregnant women to eat in food, but supplement strengths may not be; avoid them if you are pregnant or breastfeeding. Consult your doctor before taking a garlic supplement, no matter your condition.
