The most common deaths result from lung, colorectal, stomach, liver, and breast cancers. 3 Medicinal plants have played a significant part as sources of anticancer compounds. Examples of anticancer agents derived from plants include the vinca alkaloids from Madagascar periwinkle, isoquinoline alkaloids from the Opium poppy, camptothecin derivatives from camptotheca spp, taxane derivatives from Pacific yew tree, podophyllotoxin derivatives from Mayapple, and cannabinoids from cannabis. 4 The investigation of plants continue to hold a promise for the treatment of cancer. In this study, extracts of flower buds, young flower buds, leaves and young leaves of S. aromaticum were evaluated for their cytotoxic activity against A549 (lung carcinoma), HT-29 (colorectal adenocarcinoma), Hela (cervical adenocarcinoma), and MDA-MB-231 (breast adenocarcinoma) cell lines. The study also intends to validate the plant extracts as an alternative source of anticancer agents. Furthermore, a comparative analysis of phenolic compounds in the plant extracts was carried out. Materials and Methods Plant material and chemicals S. aromaticum sample was collected from Chanthaburi province, Thailand in September 2020, and identified by Apiradee Korpphaiboon, a Botanist in the Department of Agriculture, Chanthaburi Horticultural Research Center. A Voucher specimen number #10102 was assigned. The plant material was washed to remove contaminants and dried at 50 o C in a hot air oven for 24 h. The plant samples were separately pulverized in a blender and stored at room temperature, away from light. Dulbecco's Modified Eagle Medium (DMEM), fetal bovine serum (FBS), glutamine, penicillin, and streptomycin were purchased from Invitrogen (USA). MTT reagent (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide)