Garlic Uses, Side Effects & Warnings (2024)

Generic name: garlic [GAR-lik]
Brand names: Garlic Oil, Garlix
Dosage forms: oral capsule (-), oral tablet (-)
Drug class: Herbal products

Medically reviewed by Drugs.com on Apr 3, 2024. Written by Cerner Multum.

What is garlic?

Garlic is an herb also known as Ail, Ajo, Allii Sativi Bulbus, Allium, Allium sativum, Camphor of the Poor, Da Suan, Lasun, Lasuna, Nectar of the Gods, Poor Man's Treacle, Rason, Rust Treacle, or Stinking Rose.

Garlic is a commonly used food and flavoring agent. When used as a food product, garlic is not likely to produce health benefits or side effects. When used as a medicinal product, garlic may produce both desired and unwanted effects on the body.

Garlic products sold as health supplements may vary widely in amount of allicin, the active ingredient in garlic. Allicin is unstable and can be reduced in garlic products that are aged to reduce odor. Odorless garlic may contain little to no allicin. The lower the amount of allicin, the less effective a garlic product might be.

Garlic taken orally (by mouth) has been used in alternative medicine as a possibly effective aid in treating high blood pressure, coronary artery disease (hardened arteries), stomach cancer, colon cancer or rectal cancer, and in preventing tick bites. Garlic applied to the skin may also be possibly effective in treating fungal skin infections such as ringworm, jock itch, or athlete's foot.

Garlic has also been used to treat high cholesterol, stomach ulcers caused by H. pylori, cancer, or circulation problems in the legs. However, research has shown that garlic may not be effective in treating these conditions.

Other uses not proven with research have included preventing the common cold, and improving urination problems caused by an enlarged prostate.

It is not certain whether garlic is effective in treating any medical condition. Medicinal use of this product has not been approved by the FDA. Garlic should not be used in place of medication prescribed for you by your doctor.

Garlic is often sold as an herbal supplement. There are no regulated manufacturing standards in place for many herbal compounds and some marketed supplements have been found to be contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.

Garlic may also be used for purposes not listed in this product guide.

Garlic side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Although not all side effects are known, garlic is thought to be possibly safe when taken for a short period of time.

Stop using garlic and call your healthcare provider at once if you have:

• redness, swelling, or blistering (when applied to the skin); or

• easy bruising or bleeding (nosebleeds, bleeding gums).

Common side effects (especially when eating raw garlic) may include:

• unpleasant breath or body odor;

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• heartburn, burning in your mouth or throat;

• nausea, vomiting, gas or

• diarrhea.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Warnings

Follow all directions on the product label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not use garlic if you are allergic to it.

Ask a doctor, pharmacist, or other healthcare provider if it is safe for you to use this product if you have:

• a stomach ulcer;

• problems with digestion; or

• a bleeding or blood clotting disorder such as hemophilia.

Ask a doctor before using garlic if you are pregnant or breastfeeding.

The use of garlic as a flavoring agent in foods is considered safe during pregnancy.

Do not give any herbal/health supplement to a child without medical advice. Garlic taken by mouth in large doses may be harmful to children.

How should I take garlic?

When considering the use of herbal supplements, seek the advice of your doctor. You may also consider consulting a practitioner who is trained in the use of herbal/health supplements.

If you choose to use garlic, use it as directed on the package or as directed by your doctor, pharmacist, or other healthcare provider. Do not use more of this product than is recommended on the label.

Do not use different forms (cloves, tablets, oil, etc) of garlic at the same time without medical advice. Using different formulations together increases the risk of an overdose.

Do not crush, chew, or break an enteric coated pill. Swallow it whole. The pill has a special coating to protect your stomach. Breaking the pill will damage this coating.

Call your doctor if the condition you are treating with garlic does not improve, or if it gets worse while using this product.

Garlic can affect blood-clotting and may increase your risk of bleeding. If you need surgery, dental work, or a medical procedure, stop taking garlic at least 2 weeks ahead of time.

Store at room temperature away from moisture, heat, and light, or as directed on the package.

What happens if I miss a dose?

Skip the missed dose and take the next regularly scheduled dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking garlic?

Avoid taking fish oil or vitamin E while you are taking garlic.

Also avoid using garlic together with other herbal/health supplements that can also affect blood-clotting. This includes angelica (dong quai), capsicum, clove, danshen, ginger, ginkgo, horse chestnut, panax ginseng, poplar, red clover, turmeric, and willow.

What other drugs will affect garlic?

Do not take garlic without medical advice if you are using any of the following medications:

• acetaminophen (Tylenol);

• birth control pills;

• chlorzoxazone;

• cyclosporine;

• theophylline;

• warfarin (Coumadin, Jantoven);

• HIV or AIDS medicines--delavirdine, efavirenz, nevirapine, saquinavir;

• medicine used to prevent blood clots, such as alteplase, clopidogrel, dipyridamole, ticlopidine, and urokinase; or

• NSAIDs (nonsteroidal anti-inflammatory drugs)--aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib, diclofenac, indomethacin, meloxicam, and others.

Do not take garlic without medical advice if you are using a medication to treat any of the following conditions:

• any type of infection (including HIV, malaria, or tuberculosis);

• anxiety or depression;

• asthma or allergies;

• cancer;

• erectile dysfunction;

• heartburn or gastroesophageal reflux disease (GERD);

• high blood pressure, high cholesterol, or a heart condition;

• migraine headaches;

• psoriasis, rheumatoid arthritis, or other autoimmune disorders;

• a psychiatric disorder; or

• seizures.

This list is not complete. Other drugs may affect garlic, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Popular FAQ

Further information

• Consult with a licensed healthcare professional before using any herbal/health supplement. Whether you are treated by a medical doctor or a practitioner trained in the use of natural medicines/supplements, make sure all your healthcare providers know about all of your medical conditions and treatments.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circ*mstances.

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