Abstract: Seaweed may belong to one of several groups of multicellular algae: the red algae, green algae and brown algae. As these three groups are not thought to have a common multicellular ancestor, the seaweeds are a paraphyletic group. In addition, some tuft-forming bluegreen algae (Cyanobacteria) are sometimes considered as seaweeds, seaweed is a colloquial term and lacks a formal definition. These can be used human food, cosmetics, fertilizers and for the extraction of industrial gums and chemicals. According to prior reports, it has been proved that so many biologically active compounds are present in seaweeds those we can use them as therapeutic agent, dietary supplements.