Trapa natans L. is annual aquatic plant generally kwon as Water caltrp, Water chest nut belonging to the Trapaceae or Lytraceae family. Trapa natans L. is use for the treatment of wide no of disease with out proper toxicity study. The present study was designed to evaluate the acute and sub-acute toxicities of Trapa natans L following the OECD guidelines. In acute oral toxicity, the plant extract was administered orally at the doses of 300 mg/kg, 1000 mg/kg, 2000 mg/kg, and 4000 mg/kg. After the dosing, all animals were kept in close observation for 14 days. In the case of the subacute toxicity study, the total number of animals was divided into four groups, each having ten animals, 5 males, and 5 females in each group. Group I was represented as the control, administered orally with aqueous tween 80 solution 2% (v/v), and group II to group IV received plant extract of doses 400, 600, and 1000 mg/kg, respectively, once a day for 28 days. From the acute and subacute toxicity studies, no sign of toxicity was observed. In the sub-acute toxicity study, no major changes were noted on the biochemical parameters and hematological analysis. The experimental results of the toxicity studies suggested that the LD50 values of the Trapa natans L extract were more than 4000mg/kg and thus, the drug was found to be absolutely safe and nontoxic.