This study investigated the toxic effects of an extract of Meswak from Salvadora persica for 30 days on the reproductive system of the mouse. The results showed that exposure to Meswak extract did not have much effect on female mouse fertility, although it caused a significant decrease in the relative weights of the ovary and an increase in uterine weights. Exposure of male mice to Meswak extract resulted in a 72% reduction in pregnancies in untreated females impregnated by test males. The relative weights of the testes and preputial glands were significantly increased and that of the seminal vesicles was significantly decreased in test males. The results indicate that Meswak has adverse effects on male and female reproductive system and fertility.