Garlic may have positive effects in preventing cardiovascular diseases, such as heart attack or stroke. Garlic helps to prevent atherosclerosis through the actions of its sulfur compounds and its ability to reduce the fatty substances, such as cholesterol, found in the bloodstream. It promotes the regression of fatty deposits in blood vessels, a major cause of atherosclerosis, and can even help reverse arterial blockages caused by the collection of plaque. Garlic significantly lowers blood levels of triglycerides which have been associated with an increased risk of heart attack. It also works as an immune system stimulant which helps the body fight bacterial, viral and fungal infections.