Microalgae exists as highly diversified photosynthetic microorganisms which are potentially valuable and are used in food, cosmetics, pharmaceutical and aquaculture industries. Numerous therapeutic compounds have been isolated from microalgae and have been tested for different types of bioactivity with positive effects. With cancer taking such a toll on the population, both in lives and cost, the discovery of anticancer drugs has become very important. However a small percentage of the marine microalgae population has been investigated thoroughly for their pharmaceutical potential. In consideration the present study was focused on Isolation, molecular identification and laboratory culture of marine microalgae; Screening of crude microalgae extracts against bacterial pathogens; Immunomodulatory, hypolipidimic and antitumor properties of microalgae extracts in normal and DLA induced albino mice model. Acute and sub-acute toxicity effects of microalgae active principles were also studied. This research work shall be especially useful for researchers in the field of marine biology; immunology; microbiology and preclinical research.