摘要:Fragrant pennyroyal (Mentha pulegium) from Lamiaceae family has many medicinal properties likehaematopoietic enhancement. The effect of hydro alcoholic extract of pennyroyal on blood parameters ofmice was studied on little laboratory mice from Balb/C race. Fifty mice were divided in five groups: controlgroup, Placebo (0.6 cc of normal saline), and three extract treatment groups (50, 100, and 200 mg/kg/2days). Peritoneum injection was used for enforcing treatments. Blood samples were taken from mice hearts.Data were analysed using SPSS program at 5% probability level. Results showed that total number of whiteblood cells was increased significantly in third treatment group (200 mg/kg). Red blood cells also increasedsignificantly in this group. Haemoglobin was increased in all treatment groups but haematocrit and bloodindices (MCHC, MCH, MCV) did not show any significant effect. According to the results, pennyroyal extractcan strengthen immune system in 200 mg/kg dose via increase in number of white blood cells and can affecthaematopoietic via increase in number of red cells.