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Botanical name(s):

Allium sativum. Family: Liliaceae

General description

Garlic consists of fresh or dried bulbs of the botanical plant Allium sativum. It’s cultivated worldwide. The bulb, or clove, is the part of the plant that’s used most often. Garlic is best stored hung in a dry place. Garlic can be consumed fresh, as a powder sprinkled over food, or as garlic oil to flavor foods.

Garlic contains alliin. When this is ground, it makes the strong-smelling, potent antibacterial agent allicin. Garlic may have antibacterial effects. It’s also said to protect against conditions related to the heart and blood vessels that cause atherosclerosis and stroke. This is because it keeps platelets from sticking together. It may also lower high blood pressure and cholesterol.

Medically valid uses

Some animal studies suggest that garlic may improve insulin release, but there is no evidence to support this effect in humans.

Other studies show that garlic may improve the elasticity of the aorta. It may also keep atherosclerotic plaque from forming.

There is some evidence that says garlic can slightly lower cholesterol levels. But recent research done by the National Center for Complementary and Integrative Health found that garlic has no effect on cholesterol.

Some research shows that taking garlic by mouth can modestly reduce blood pressure. This effect was seen in people with high blood pressure. It was also seen in people with normal blood pressure. The evidence indicates that garlic, when used with a knowledgeable healthcare provider, can help lower blood pressure in people with hypertension.

Unsubstantiated claims

There may be benefits that have not yet been proven through research.

Some reports suggest that garlic may help prevent or treat cancer.

Garlic contains allicin. This is a strong antibiotic. It’s released when cloves are crushed or chewed. Garlic has been used as an antiseptic, antibacterial, and antifungal agent. It may help the body resist or destroy viruses and other microorganisms. It does this by boosting the immune system.

Garlic is also claimed to fight infections. It may also build up strength. Garlic may also have laxative effects.

Garlic may also help treat these issues:

  • Chronic bronchitis

  • Chronic mucus in your nose and throat (catarrh)

  • Recurrent colds and respiratory infections

  • Chronic earaches

  • Sore throat

  • Sinus problems

  • Flu

  • Yeast infections

  • Intestinal worms

Dosing format

Garlic is available fresh or dried in oral capsule form. The enteric-coated capsules are easiest for the body to absorb. It also comes as an extract and as odorless supplements. The quality of commercial forms of garlic varies a lot.

Use garlic exactly as directed on the label.

Side effects, toxicity, and interactions

Garlic has a strong taste and odor. Raw garlic can cause stomach upset in some people. Odorless garlic supplements get rid of the strong taste and odor. They may also reduce stomach upset.

Some people are allergic to garlic. When taken in large amounts, garlic may cause side effects. These include causing stomach ulcers and anemia.

Garlic can interact with certain medicines. Using supplements of garlic that contain allicin for a long time may decrease how well saquinavir (a medicine used to treat HIV) works. If you’re taking this medicine, talk with your healthcare provider before using garlic. Be careful when taking blood thinner medicines, as garlic may increase the risk of bleeding.

Online Medical Reviewer: Bianca Garilli MD
Online Medical Reviewer: Chris Southard RN
Online Medical Reviewer: Stacey Wojcik MBA BSN RN
Date Last Reviewed: 8/1/2023
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