Background: Barberry (Berberis vulgaris L. family Berberidaceae) is well known in Iran, and various parts of this plant including its root, bark, leaf and fruit have been used in folk medicine. There are evidences that this plant contains several antibacterial agents and has been used as a food additive.

Objective: This experiment was conducted to evaluate the effects of Berberis vulgaris root powder in the diets of broiler chickens on growth performance.

Methods: One hundred thirty Arbor Acers day old chicks from both sexes (mean of Body weight: 40 g) were divided into two equal groups in a completely randomized design. Dried roots of Berberis vulgaris were powdered and added to the ration of experimental group at a rate of 1%. The measured traits in this study were: live body weight, feed consumption and eventual side effects (gross and histopathological lesions). Tissue samples of heart, liver and skeletal muscles were collected and fixed in 10% buffered formalin for histopathologic examination. Data were analyzed by two independent sample t-test, using SPSS/PC software.

Results: At six weeks of age, there was a significant and greater weight gain in chickens of experimental group (means ± S.D in experimental groups was 1822.2 ± 75.1 g versus 1662.8 ± 85.2 g in control group) (p≤0.05).