Rambutan (Nephelium lappaceum L.) is a plant native to Indonesia that has a variety of potential pharmacological activities. In this study, we evaluated acute and sub-chronic administration of rambutan peel extract. In the acute toxicity study, rambutan peel extract was administered at doses of 400; 1,400; 4,900 and 17,150 mg/Kg BW for 24 hours in order to assess toxic effects that occurred. In subchronic toxicity study, the rambutan peel extract was administered at doses of 3,500 and 6,400mg/kg BW performed for 90 days in wistar rats. The results acute toxicity showed that a high dose of 17,150 mg/kg BW no rats were death after 24 hours oral administration. It could be concluded that extract with LD-50 is categorized as practically non-toxic. Administration of rambutan peel extract at high dose did not induce weight changes significantly. Rambutan peel extract did not affect to urine volume. Liver function at base line and at 45th days based on levels of SGPT and SGOT, dose 3.5 and 6.4 g/kg b.w compared to normal control were not different. While at 90th days dose 3.5 and 6.4 g/kg b.wt SGPT levels were increased. Creatinine and urea levels of groups and normal control were same. Blood parameters such as, hematocrit, hemoglobin, red blood cells, white blood cells, and platelets showed a profile that was almost the same as the control group. Based on data, it could be concluded that oral administration of rambutan peel extract on acute and sub chronic toxicity was safe. Keywords: Rambutan; toxicity studies; rats