$Streblus$ $asper$ Lour (Family: Moraceae) is a medicinal plant wildly grows in most part of Asian countries. It has many traditional uses like leprosy, piles, diarrhoea, dysentery, elephantiasis, cancer etc. This present study was relates in terms of behavioural safety and toxicity studies of methanol and petroleum ether extracts of $S.$ $asper$. Brine Shrimps lethality bioassay method was established for the present study and cytotoxicity was reported in terms of 50% lethality concentration ($LC_{50}$). Different concentrations of drug solutions were added to the Brine Shrimps, surviving shrimps were counted after 24 h and 50% lethality concentration ($LC_{50}$) were assessed. Acute toxicity was studied on Swiss albino mice after single dose. Sub-Chronic toxicity was performed for 28 days and assessed with biochemical and histopathological parameters. On cytotoxicity studies of brine shrimps it was found methanol extract of $S.$ $asper$ (MESA) was weakly toxic, may be due to the presence of cardiac glycosides and bioactive compounds, however petroleum ether extract of $S.$ $asper$ (PESA) was non toxic. But, in case of acute and sub-acute toxicity study both extracts were found to be non-toxic.