In this study, the acute and subchronic toxicity effect of the Syzygium aqueum leaf extract (SA) was evaluated. For the acute toxicity study, a single dose of 2000. mg/kg of the SA was given by oral-gavage to male Sprague-Dawley (SD) rats. The rats were observed for mortality and toxicity signs for 14 days. In the subchronic toxicity study the SA was administered orally at doses of 50, 100, and 200. mg/kg per day for 28 days to male SD rats. The animals were sacrificed at the end of the experiment. The parameters measured including food and water intake, body weight, absolute and relative organ weight, blood biochemical tests and histopathology observation. In both the acute and subchronic toxicity studies, SA did not show any visible signs of toxicity. There were also no significant differences between the control and SA treated rats in terms of their food and water intake, body weight, absolute and relative organ weight, biochemical parameters or gross and microscopic appearance of the organs. There were no acute or subchronic toxicity observed and our results indicate that this extract could be devoid of any toxic risk. This is the first in vivo study reported the safety and toxicity of SA.