Background and purpose: Alopecia areata is the rapid onset of total hair loss in a sharply defined round area. No definite cause is known for this disease but stress is an effective factor. Different treatments are available but no cure is yet known. The purpose of this study is to determine the efficacy of garlic gel in treatment of alopecia areata.Materials and Methods: The method of study is placebo controlled. The study was performed during summer 2004-5. The subjects were recruited from dermatology clinics in the city of Sari, according to inclusion criteria. They were randomly divided into 4 blocks and received gel and placebo. Garlic gel was used twice dayly with topical corticosteroid. The results were compared together after 3 months. The data were analyzed by ANOVA and Tuky-test using SPSS program. Results: Twenty patients were given the garlic gel and placebo was administered to the other 20 patients. The average age of the patients (55% male) was 24 ± 15. Scalp was the most common affected area in patients (72.5 %) and majority of them had one patch (70 %). Positive familial history was noted in 22.5 % of the patients and 25 % of them had the atopic. Stress was observed in 35% of the patients. There was no difference in decreasing the size of patches in the first two months, between the two groups. However, the increase in the number of hair between the two groups were significant in the third month(P<0.05). Conclusion: The garlic gel can stimulate hair growth in patients with Alopecia areata. Therefor this effective and low cost treatment is recommended particularly for limited forms of the disease