P LANTS have been used as a source of traditional medicine to treat many diseases and conditions for many years. They considered as excellent source of phytochemicals which showed antioxidant and anticancer activities. The aim of the present study is to investigate the chemical composition and to determine the anticancer activity of Salicornia fruticosa (Chenopodiaceae) methanolic extract. S. fruticosa proved to be a source of isorhamnetin and its glycosides and showed anticancer activities. Seven major flavonoids were isolated and identified from the cytotoxic methanolic extract. The isolated compounds were identified, as quercetin 3',4'-dimethyl ether (1), isorhamnetin (2), isorhamnetin 3-O-rhamnoside (3), isorhamnetin 3-O-glucoside (4), isorhamnetin 3-O-rutinoside (5), isorhamnetin 3-O-neohesperidoside (6), isorhamnetin 3-O-rhamnosyl(1-2)arabinoside (7), by chromatographic analysis, chemical and spectroscopic tools (acid hydrolysis, UV, 1 H and 13 C NMR). Compounds 1 and 3-7 were isolated for the first time from the plant under investigation. The evaluation of cytotoxic activity of the methanolic extract against HCT-116, HepG2, A549 and MCF-7 human cancer cells, by MTT assay, revealed the higher potency of S. Fruticosa extract with IC 50 [2.6. 10.9, 37.9, 5.4 (mg/ml)] respectively, comparable to that of doxorubicin. The obtained results suggested that the investigated plant could be used for future development of naturally occurring anticancer agent. Subclinical and clinical trials on polar fractions of S. fruticosa are mandatory to pave the way for its use in treatment of cancer diseases (HCT-116, HepG2, A549 and MCF-7).