Garlic is in the allium family along with onions, scallions, shallots, leeks, and chives.  Studies have shown that most of the health benefits are related to chopping the clove and releasing the sulfur compounds.  One of the compounds Allicin can inhibit the proliferation of both bacteria and fungi or kill cells outright, including antibiotic-resistant strains like methicillin-resistant Staphylococcus aureus (MRSA) and it induces cancer cell-death and inhibits its proliferation. 

Diallyl disulfide and s-allyl cysteine are known to protect against neuro-inflammation a cause of cognitive deficit and dementia. A randomized controlled study gave folks a placebo (fake pill) or an allicin-containing garlic supplement daily. Those taking the garlic supplement reported less incidents of colds and or flu symptoms and faster recovery if symptoms did occur. 

Garlic has been shown to help decrease blood pressure as well as some beta blockers. Garlic has been shown to decrease total cholesterol by up to 12%. Garlic has been shown to contain antioxidant phytochemicals that prevent oxidative damage. Some findings point out the beneficial effects of garlic supplementation in reducing blood pressure and counteracting oxidative stress, and thereby, offering cardio-protection in essential hypertensive peeps. 

Garlic can be recommended for the treatment of mild-to-moderate lead poisoning.