Naturally found growing in the United States and many other regions of the world, herbalists everywhere consider garlic to be one of the most important and effective medicinal herbs. It has been used as both food and medicine in many cultures for thousands of years and continues its popularity even today.

The Miracle of Garlic

For many decades, people have been using garlic and garlic based supplements to prevent a myriad of health conditions including atherosclerosis, high blood pressure, flu, colds, coughs, bronchitis, gastrointestinal problems, and menstrual pain. Studies have shown that garlic can kill many types of bacteria, some viruses, a number of fungal infections, and in some cases even intestinal parasites. Additionally, garlic is also considered an effective antioxidant that can boost the body's immune system and may even help prevent certain cancers such as colon cancer.

However, garlic is best known for its favorable effects on cardiovascular health. Garlic is believed to be effective in preventing and treating high cholesterol and triglyceride levels, atherosclerosis, and respiratory infections. One study reported that Garlic was able to reduced arterial plaque formation by nearly 20 in some participlants, the benefits being most notable in women.

The primary active ingredient in garlic is alliin. Alliin is an odorless chemical that is similar in chemical structure to the sulfur-containing amino acid, cysteine. When garlic bulbs are crushed, alliin is converted into another compound called allicin which in turn produces other compounds: ajoene, allyl sulfides, and vinyldithiins. Allicin and its deratives are what give garlic its characteristic odor and many of its medicinal effects.

Side Effects and Possible Interactions

Aside from the smell, no severe side effects have been reported by those taking garlic supplements.

There have been reports of a possible interaction between garlic and warfarin that could increase risk of bleeding. Therefore, if you are taking anticoagulant (blood-thinning) medications such as aspirin, warfarin, dipyridamole, or indomethacin, you should refrain from consuming large amounts of garlic, either fresh or commercially processed.

Dosage and Administration

The most common form of garlic supplementation is in capsules. In capsule form, a commonly recommended dosage is 1000 to 3000 mg daily. In oil form take 0.03 to 0.12 mL three times a day. However, always follow manufacturers recommendations.

Supporting Literature

Ackermann RT, Mulrow CD, Ramirez G, Gardner CD, Morbidoni L, Lawrence VA. Garlic shows promise for improving some cardiovascular risk factors. Arch Intern Med. 2001;161:813-824.

Berthold HK, Sudhop T. Galic preparation for prevention of atherosclerosis. Curr Opin Lipidol. 1998:565-569.

Fugh-Berman A. Herbs and dietary supplements in the prevention and treatment of cardiovascular disease. Prev Cardiol. 2000;3:24-32.

Isaacsohn JL, Moser M, Stein EA, et al. Garlic powder and plasma lipids and lipoproteins. Arch Intern Med 1998;158:1189-1194.

Koscielny J, Klüendorf D, and Latza R.The antiatherosclerotic effect of Allium sativum. Atherosclerosis 1999;144:237-249.

McCrindle BW, Helden E, and Conner WT. Garlic extract therapy in children with hypercholesterolemia. Arch Pediatr Adolesc Med 1998;152:1089-1094.

Silagy C, Neil A. Garlic as a lipid-lowering agent-a meta-analysis. J R Coll Phys London 1994;28:39-45.

Warshafsky S, Kamer R, and Sivak S. Effect of garlic on total serum cholesterol: A meta-analysis. Ann Int Med 1993;119:599-605.