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The Blog Spot

Garlic and the Immune System

In part eight of this series about the immune system, we are going to discuss garlic and the benefits it has on the immune system. In future weeks we will further explore other herbs and spices that can help with boosting the immune system.

Common Name: garlic (1)

Latin Name: Allium sativum (1)

History: Garlic is commonly used in cooking, especially in the cooking of Italian dishes. Garlic is an edible bulb who comes from the lily family. It is believed that garlic is native to Siberia and has been used for over 5000 years (3). Historically, garlic was used for health reasons in Egypt, Greece, Rome, China, Japan, and by Native Americans. Today, garlic continues to be used as a dietary supplement for many health conditions including high blood cholesterol, high blood pressure, colds, and for the prevention of cancer and other diseases (1)

Garlic contain an odorless, sulfur-containing amino acid called alliin. When garlic is crushed, the alliin connects with the enzyme alliinase and is then converted to allicin. Therefore, it is important to slightly tap or crush your fresh garlic and allow it to sit for 10 minutes before adding it to your cooking pan in order to get the therapeutic properties from garlic! Allicin is a powerful antibiotic and has antiplatelet, antibiotic, and antihyperlipidemic properties (2).

Garlic potentially has the ability to stimulate both humoral and cellular immunity. This sets of a reaction that leads to the multiplying of T-cells, restoration of suppressed antibody responses, and the stimulation of macrophage cytotoxicity on tumor cells.

Garlic may also increase the absorption of selenium which could offer protection against tumorigenesis. Garlic may also protect against some cancers by stopping “cell cycle progression and inducing apoptosis of cancer cells as well as by decreasing angiogenesis and influencing carcinogen metabolism” (2).

Immune (and other) Benefits (2)

  • Microbial infection

  • Skin infections

  • Atherosclerosis

  • Cancer prevention

  • Cancer treatment

  • Cardiovascular disease

  • Circulatory disorders

  • High cholesterol

  • Hypertension

  • Garlic oil can be used on the skin or nails to treat fungal infections (3)

  • Yeast infections (3)

Side Effects (2)

  • Headache

  • Fatigue

  • Altered platelet function with potential for increased bleeding (2, 3)

  • Offensive odor, bad breath

  • Stomach upset

  • Diarrhea

  • Changes in the natural bacteria found in the intestines

  • Sweating

  • Low blood sugar

  • Contact dermatitis (inflammation, redness of the skin) when used topically.


  • Discontinue garlic use at least 7 days before surgery (2)

Herb and Drug Interactions

  • Insulin: Insulin may need to be adjusted due to hypoglycemic effects of garlic (2)

  • Warfarin: Anticoagulant activity may be enhanced by garlic (2)

  • Saquinavir (Fortovase, Invirase): Consuming garlic can significantly decrease serum concentration levels (2)

  • Cytochrome (CYP) P450 substrates: Garlic can inhibit CYP 2C9, 2C19, 3A4 and may interfere with the drugs metabolized by these enzymes (2)

  • P-Glycoprotein substrates: Garlic induces P-glycoprotein and can interfere with the metabolism of certain drugs (2)

  • Birth Control Pills: Garlic might decrease effectiveness of the pill (3)

Herb and Lab Interactions

  • Insulin

  • Increased PT and INR

  • Decreased cholesterol

  • Change in blood pressure

If you have an acute or chronic health condition or take medications, you should consult with your health care provider before taking any new herbs or spices.

Interested in taking a garlic supplement? HERE is one Kim recommends, though she prefers that you use garlic daily in cooking vs. using a supplement!

HERE is a great creamy garlic soup recipe!

About the Author: Leanne DiMaio earned her Master’s degree in Applied Clinical Nutrition from New York Chiropractic College in December 2017. She is currently working on her Doctorate degree in Clinical Nutrition at Maryland University of Integrative Health. Leanne is passionate about helping others achieve their optimal state of health and wellness. She is currently earning clinical hours toward the Certified Nutrition Specialist (CNS) credential under Kim Ross's supervision.


1. National Center for Complementary and Integrative Health (NCCIH). Garlic. NCCIH. Published 2016. Accessed September 23, 2018.

2. Memorial Sloan Kettering Cancer Center. Garlic. Published 2018. Accessed September 23, 2018.

3. Web MD. Garlic: Uses, Side Effects, Interactions, Dosage, and Warning. Published 2018. Accessed September 23, 2018.

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