Garlic may have positive effects in preventing cardiovascular diseases. Garlic may also help to prevent atherosclerosis through the action 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 may help reverse arterial blockages caused by the collection of plaque. Garlic may lower blood levels of triglycerides which have been associated with an increased risk of heart attack. It also works as an immune system stimulant which may help the body fight bacterial, viral and fungal infections.