Objective: Scaevola taccada. (Gaertn.) Roxb. is widely dispersed all along the coasts of Africa. It is used in folk medicine for diversity of ailments. This study aims to investigate the major phytoconstituents and biological activities of the leaves of S. taccada (Gaertn.) Roxb. Methods: In vitro biological examination viz. antimicrobial, cytotoxic and antioxidant activities of the ethanol extract of the leaves (EE) and its fractions; (petroleum ether (PE), methylene chloride (MC), ethyl acetate (EA) and n-butanol(BuOH)) were carried out. Estimation of the phytochemicals of biologically active fractions was done. Results: n-butanol fraction displayed remarkable antimycobacterium activity. Petroleum ether as well as n-butanol fractions evidenced a cytotoxic effect on breast carcinoma cell line (MCF7) and colon carcinoma cell line (HCT) with IC50 11.7 and 15.04 µg/ml respectively. Moreover, ethyl acetate fraction exhibits an antioxidant effect with EC50 476.7±0.57 µg/ml. n-tetradecane 1, α-amyrin palmitate 2, α-amyrin acetate 3, α-amyrin 4, stigmasterol 5, luteolin-7-O-β-glucoside 6, rutin 7 and alidyjosioside 8 were identified in S. taccada (Gaertn.) Roxb. leaves. Conclusion: Petroleum ether fraction is a cytotoxic candidate, especially against (MCF-7). It exhibited a moderate antifungal and antibacterial against certain Gram-positive bacteria. Ethyl acetate showed an antioxidant effect along with moderate antifungal activity. n-butanol fraction exerted potential antimycobacterial, significant cytotoxic activity against (HCT), good antifungal and antibacterial against Gram-positive and Gram-negative bacteria. Stigmasterol, luteolin-7-O-β-glucoside, rutin and alidyjosioside were isolated for the first time from S. taccada (Gaertn.) Roxb. Leaves.