The objective of this study was to investigate the effectiveness of oral Aloe vera juice in a group of patients with mild-to-moderate acne vulgaris. In this double-blind, placebo-controlled, randomized clinical trial, 40 volunteers with mild-to moderate acne vulgaris were randomized equally into two, age and sex-matched groups, receiving either 50 cc of freshly prepared Aloe vera (Aloe barbadensis Miller) juice or placebo once daily for 30 consecutive days. Facial acne noninflamed, inflamed and total lesion counts were documented at baseline on week 2 and at endpoint by an observer who was blind to the grouping of patients. There were 12 males and 8 females with a mean age of 17.5±5.1 years in the case group and 10 males and 10 females with a mean age of 17.4±5.6 years in the control group. Although, the mean number of inflamed and total acne lesions decreased from baseline to the endpoint in the case group, these changes were not statistically different from those documented in the control group.