Health Benefits Of Garlic
In in vitro studies, garlic has been found to have antibacterial, antiviral, and antifungal activity. However, these actions are less clear in vivo. Garlic is also claimed to help prevent heart disease (including atherosclerosis, high cholesterol, and high blood pressure) and cancer. Animal studies, and some early research studies in humans, have suggested possible cardiovascular benefits of garlic. A Czech study found garlic supplementation reduced accumulation of cholesterol on the vascular walls of animals. Another study had similar results, with garlic supplementation significantly reducing aortic plaque deposits of cholesterol-fed rabbits. Another study showed supplementation with garlic extract inhibited vascular calcification in human patients with high blood cholesterol. The known vasodilative effect of garlic is possibly caused by catabolism of garlic-derived polysulfides to hydrogen sulfide in red blood cells (RBCs), a reaction that is dependent on reduced thiols in or on the RBC membrane. Hydrogen sulfide is an endogenous cardioprotective vascular cell-signaling molecule.
In 2007, the BBC reported Allium sativum may have other beneficial properties, such as preventing and fighting the common cold. This assertion has the backing of long tradition in herbal medicine, which has used garlic for hoarseness and coughs. The Cherokee also used it as an expectorant for coughs and croup. However, in contrast to these earlier claims concerning the cold- preventing properties of garlic, a 2012 report in the Cochrane Database of Systematic Reviews concludes that “there is insufficient clinical trial evidence regarding the effects of garlic in preventing or treating the common cold. A single trial suggested that garlic may prevent occurrences of the common cold but more studies are needed to validate this finding. Claims of effectiveness appear to rely largely on poor-quality evidence.”
Garlic is also alleged to help regulate blood sugar levels. Regular and prolonged use of therapeutic amounts of aged garlic extracts lower blood homocysteine levels and has been shown to prevent some complications of diabetes mellitus. People taking insulin should not consume medicinal amounts of garlic without consulting a physician.
Garlic was used as an antiseptic to prevent gangrene during World War I and World War II. More recently, it has been found from a clinical trial that a mouthwash containing 2.5% fresh garlic shows good antimicrobial activity, although the majority of the participants reported an unpleasant taste and halitosis.
Garlic cloves are used as a remedy for infections (especially chest problems), digestive disorders, and fungal infections such as thrush. Garlic can be used as a disinfectant because of its bacteriostatic and bactericidal properties.
In 1924, it was found to be an effective way to prevent scurvy, because of its high vitamin C content.
Garlic has been used reasonably successfully in AIDS patients to treat Cryptosporidium in an uncontrolled study in China.  It has also been used by at least one AIDS patient to treat toxoplasmosis, another protozoal disease. Garlic supplementation has been shown to boost testosterone levels in rats fed a high protein diet.
A 2010 double-blind, parallel, randomized, placebo-controlled trial, involving 50 patients whose routine clinical records in general practice documented treated but uncontrolled hypertension, concluded, “Our trial suggests that aged garlic extract is superior to placebo in lowering systolic blood pressure similarly to current first line medications in patients with treated but uncontrolled hypertension.” http://en.wikipedia.org/wiki/Garlic