Historically, garlic has been widely used in medicine1 for circulatory and lung ailments, and modern research backs the wisdom of many of these historical claims — and more. For example, studies show that regular consumption of (primarily raw) garlic:

May be effective against drug-resistant bacteria, including MRSAReduces risk for heart disease,2 including heart attack3 and strokeHelps normalize your cholesterol4 and blood pressureHelps protects against cancer,5,6 including brain,7 lung8 and prostate9 cancerReduces your risk of osteoarthritis10

Many of its therapeutic effects comes from sulfur-containing compounds such as allicin, which also give garlic its characteristic smell. As allicin is digested, it produces sulfenic acid,11 a compound that reacts with dangerous free radicals faster than any other known compound. Other health-promoting compounds include oligosaccharides, arginine-rich proteins, selenium and flavonoids.12

Garlic must be fresh to give you optimal health benefits, though. The fresh clove must be crushed or chopped to stimulate the release of an enzyme called alliinase, which in turn catalyzes the formation of allicin.13 Allicin in turn rapidly breaks down to form a number of different organosulfur compounds. So, to activate garlic’s medicinal properties, compress a fresh clove with a spoon prior to swallowing it, or put it through your juicer to add to your vegetable juice.

A single medium size clove or two is usually sufficient, and is well-tolerated by most people. Allicin is destroyed within one hour of smashing the garlic, so garlic pills are virtually worthless. You also won’t reap all the health benefits garlic has to offer if you use jarred, powdered or dried versions.