Garlic

Studies in people

• Benefit

  Blood pressure²

  Garlic may modestly lower blood pressure, but scientists do not yet know the best dose or form.

• Benefit

  Heart and blood health³

  Eating garlic lowered blood fats, blood sugar, and blood pressure in adults, especially those already at higher risk.

• Benefit

  Heart and blood vessels⁴

  A review suggests garlic may help with mild high blood pressure, high cholesterol, and clogged arteries.

• Benefit

  Blood pressure and cholesterol⁵

  In people, garlic supplements lowered blood pressure and total cholesterol, though study quality varied.

• Benefit

  Blood fats and blood pressure⁶

  In people with high blood pressure, garlic capsules lowered blood fats and raised vitamin E, but did not change blood pressure.

• Benefit

  Cholesterol and heart health⁷

  In people with mildly high cholesterol, a garlic and onion capsule lowered LDL and total cholesterol over 8 weeks.

• Benefit

  Stomach cancer deaths⁸

  In people, taking garlic extract and oil for years was linked to fewer deaths from stomach cancer.

• Open question

  How much the body absorbs⁹

  How much allicin the body actually gets from garlic foods and pills varies a lot.

• Open question

  Heart and blood pressure¹⁰

  Garlic has been studied for heart and blood pressure effects, but the evidence so far is not strong.

• Benefit

  Bowel cancer risk¹¹

  People who ate more garlic were less likely to get bowel cancer, though the evidence is mixed.

• Benefit

  Blood pressure control¹²

  In people with uncontrolled high blood pressure, aged garlic extract lowered systolic pressure at some doses.

• Benefit

  Breast cancer risk¹³

  Women who ate more garlic and onions were less likely to get breast cancer, but this study cannot prove cause.

• Benefit

  Knee arthritis pain¹⁴

  In overweight women with knee arthritis, garlic tablets for 12 weeks lowered pain scores and a blood marker of inflammation.

• Benefit

  Blood fats after a fatty meal¹⁵

  In people, garlic and onion oils helped stop butter from raising cholesterol and clotting measures in the blood.

Animal and lab studies only

• Benefit

  Gut health and constipation¹⁸

  In mice, garlic polysaccharides strengthened the gut lining and eased constipation, but whether this happens in people is unknown.

• Benefit

  Blood clot prevention¹⁹

  In animal studies, odorless garlic powder helped blood break down clots and slowed clotting.

Study type not stated

• Concern

  Stomach upset and drug interactions¹⁶

  Garlic can upset your stomach at high doses and may change how some medicines work.

How it’s made and used

• Health benefits of traditional foods¹⁷

  Garlic has been eaten as food and used as medicine in Turkey for thousands of years.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.