A total number of 360 sexed, one day old Japanese quail were used to study the effect of using dried peppermint leaves (DPL)as natural growth promoters alternative to antibiotics at the levels  of (0, 8mg avilamycin / kg diet, 1%DPL and 3 %DPL) under the two sexes (males and females). The obtained results abbreviated as follows: Treatments significantly affected most studied traits more than sex effect did.   Females had higher LBW_38d, BWG_10-38, PI _10-38, dressing%, giblets weight and giblets% than males. Treatments  significantly affected, serum biochemical indices  (except both HDL and ALT), antioxidant parameters and immune responses and intestinal microflora count, favoring the quail fed diet supplemented with peppermint 3% which had the best growth performance. Quail fed diet appended withpeppermint 3% showed desirably  lower total cholesterol, and lower lipid profile parameters,  random blood sugar, and liver enzyme activities, had the elevated antioxidant parameters,  immune responses and the lowest thiobarbaturic acid. Peppermint (3% and 1%) supplementation desirably increased Lactobacillus count as compared with those fed diets appended with avilamycin and the control groups and decreased both E coli and Salmonella counts compared to group of control. In conclusion, peppermint can be supplemented to growing quail diets up to 3% acting as a good alternative to antibiotic (avilamycin) for promoting quail growth.