Background: The usage of “growth promoter” antibiotics has been banned recently. This is due to the possibility of bacterial resistance and the risk of transferring to consumers. Herbs with antimicrobial and hypolipidemic properties can suggest as proper alternatives for antibiotic.

Objective: Comparative investigation of growth promoting effect of four medicinal plants (Cuminum L ., Mentha piperita L ., Achillea L ., Teucrium Polium L.) on performance and concentration of serum lipids of broiler.

Methods: Total 280 day-old male Ross broiler chicks were used in a CRD design with 5 treatments, and 4 replicates and 56 birds per each treatment. Cuminum, Mentha piperita, Achillea and Teucrium Polium was added to diets in levels of 1.5, 0.3, 0.2 and 0.2 percent, respectively. A treatment without any additive was considered as control group. Feed intake, weight gain and feed conversion ratio were recorded weekly. Total cholesterol, Triglycerides, LDL and HDL were measured at 35 days of age.

Results: Among the medicinal plants that used in this study, inclusion Mentha piperita in finisher diets increased feed intake (2196.4 g) and weight gain (1005.3 g), significantly (p<0.05). At total rearing period, addition of Teucrium Polium to diets decreased weight gain (1821.3 g) of chicks compared to control (1963.7 g), decreased total cholesterol (151.33 mg/dl) and LDL (29.06 mg/dl) but it increased HDL (120.16 mg/dl) of serum (p<0.05).