Cancer is a disease that affects a person not just physically but also psychologically. The pain involved,the immense cost of treatment and side effects made the researchers to shift from allopathy to allelopathic medical cure for the treatment. Seaweeds are the marine macro-algae found to be rich in nutrients including antioxidants and various remarkable properties. Certain brown seaweeds are exhibiting excellent antioxidant activity and anticancer activity.Hence, in the present investigation three different seaweeds such as Kappaphycus alvarezii, Gracilaria verrucosa, Enteromorpha intestinalis were selected for the screening of certain biological activites. From the findings, it is highly recommended that like medicinal plants, seaweeds also possess strong antioxidant, anticancer and antibacterial properties. Hence this preliminary investigation from selected three seaweeds will help to do further studies on isolating bioactive compounds from seaweeds and detailed molecular level investigation of its antitumor potential may result in new drug discovery.