The present study was conducted to test for in vivo Brine Shrimp Lethality Assay (BSLA) of the Aqueous and ethanolic extracts of Annona reticulata with Allium fistolisum and Brassica oleraceae 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 extracts of Annona reticulata with Allium fistolisum and Brassica oleraceae were potent against the brine shrimp when compared alone with combined extracts. It indicated that bioactive components are present in these plants that could be accounted for its pharmacological effects. Thus, the results support the uses of these plant species in traditional medicine.