Healthnotes Newswire (August 24, 2000) — Garlic capsules reduce the chance of receiving tick bites, according to a study published in this week’s Journal of the American Medical Association.¹

In this double-blind trial, 50 Swedish soldiers were given 1,200 mg of encapsulated garlic per day, while another 50 soldiers were given placebo capsules. During the 18-week trial there were 30% fewer tick bites among those who took garlic than in those who took placebo. Ticks in many parts of the world, including Sweden, can carry the infectious agent responsible for causing Lyme disease (an acute inflammatory disease); a bite from an infected tick can transmit this disease. While a significant reduction in tick bites was reported, no conclusions can be made regarding garlic’s ability to repel other types of insects.

The authors did not reveal the type of garlic contained in the capsules used in the trial. Many forms of garlic are available as pills (e.g., aged garlic, odor-free garlic), and different preparations may have different effects.

Although preliminary, these data are encouraging. Few natural products have been shown by human research to be effective insect repellents. Prior research with natural products has largely focused on topical applications of volatile oils, including those from yarrow (Achillea millefolium) and lily-of-the-valley (Convallaria majalis).^{2 3} These trials found the topical oils to significantly reduce the incidence of mosquito bites under laboratory conditions but did not study the effect of the plant oils on tick bites. The current study appears to be the first test of the efficacy of an herb taken internally for prevention against insect bites.

Garlic has been shown to have broad-spectrum antibiotic activity in test tube studies.⁴ Other reports have suggested that garlic may help prevent heart disease⁵ and cancer.⁶ Although not yet investigated by researchers, in mythology, garlic also has a reputation for repelling vampires and amorous advances.