The present study was conducted to test for in vivo Brine Shrimp Lethality Assay (BSLA) of the Aqueous and ethanolic extracts Annona reticulate Linn. and Allium sativum and correlate cytotoxicity results with known pharmacological activities of the plants. Cytotoxicity was evaluated in terms of LC50 (lethality concentration). Ten nauplii were added into three replicates of each concentration of the plant extract. After 24 hours the surviving brine shrimp larvae were counted and LC50 was assessed. Results showed that the presence of alkaloids, tannins, and flavonoids could be accounted for its cytotoxic properties. In the other hand, studies have shown that the leaf extracts of Alcoholic and aqueous extract of Annona reticulata and bulbs of Allium sativum extracts exhibited cumulative activity when they were combined and compared. Thus, the results on the leaf extracts of Alcoholic and aqueous extract of Annona reticulata and bulbs of Allium sativum exhibited increase in activity support its use in traditional medicine.