Garlic has been shown to reduce the amount of arteriosclerotic plaque in the arteries of individuals with heart disease, according to results of a 4-year, double-blind, placebo-controlled trial.
Arteriosclerosis is a circulation problem that greatly increases the risk of heart attack, stroke and other heart conditions.

Researchers concluded that daily treatment with high-dose garlic (900mg standardized garlic powder) may reduce the increase in plaque volume by 6-18% or even cause a regression within 4 years.

Careful! Many people have garlic allergy & onion allergy.

See what this google search yielded:

http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=garlic+allergy