There is some evidence that shows garlic can lower blood cholesterol levels when used for 1 to 3 months. There is also limited evidence indicating that garlic may slow down hardening of the arteries (atherosclerosis), thereby slowing development of heart disease and stroke.
The evidence of garlic's effectiveness in lowering blood pressure is not clear.
Garlic appears to be safe for most adults. Most common side effects include breath and body odor, heartburn, upset stomach, and allergic reactions. These side effects are more common with raw garlic.
Garlic can slow the blood’s ability to clot. Use garlic with caution if you are planning to have surgery, dental work, or if you have a bleeding disorder or are on medications for blood thinning.
Garlic has been found to interfere with the effectiveness of saquinavir, a drug used to treat HIV infection. Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.