The current trial was aimed to examine impacts of feeding on peppermint leaves powder (PLP) andits respective L-menthol crystal (LMC) supplementations on production performance, blood biochemistry, antioxidant parameters, immunity indices, microbial content, digestibility and digestive enzymes in growing Japanese quail. At ten-day-old, 700 unsexed Japanese quail were randomly splated into seven treatments, every treatment had five replecates of twenty chicks per each. The 1^st treatment was given a normal diet (control), while other treatments from the 2^nd second to the 4^th were given a standard diet with PLP at 1.5, 2.0, and 2.5%, respectively. Groups from the 5^th to the 7^th were received a control diet plus LMC at levels of 17, 22, and 27 part per million (ppm), respectively. Trypsin and amylase levels were significantly greater in the birds fed a diet containing 27 ppm LMC and 2.5% PLP compared to the control group, but lipase levels were not significantly different.. All nutrient digestibility (ND) and economic efficiency were significantly improved in chicks fed a diet supplemented with 27 ppm LMC compared to the control. Birds that given a diet supplemented with 27 ppm LMC and 2.5% PLP had the better-feed conversion ratio, live body weight and body gain, without any influence in feed intake. Finally, birds received 27 ppm LMC and 2.5% PLP had a dramatically lower lipid amount, liver enzymes, Escherichia coli and Salmonella population and the highest T3 and T4 levels, antioxidant parameters and Lactobacilli population number with the best impregnability compared to the control group. In conclusion, the addition of LMC at 27 ppm followed by PLP at 2.5%, to the basal diet improved the nutrients digestibility, digestive enzymes, performance, antioxidant, plasma biochemical, immunological indices, intestinal microbiota and economical efficiency in Japanese quails during growing phase