Algae exhibit a very wide range of morphological diversity. The simplest forms are unicellular, microscopic and motile (or) non-motile eukaryotic cells. According to the web definitions histochemistry is the branch of science that deals with the chemical composition of the cells and the tissues of the chemical composition of the cells and tissues of the body and science the combines the techniques of biochemistry and histology in the studies of chemical constitution of cells and tissue. Fronds of Padina tetrastromatica shelter for aquatic organisms such as fishes and molluscs. Brown seaweeds are the most intensely studied type of seaweeds being composed of potentially bioactive polysaccharides such as fucoidan and alginic acid. Fucoidan from Sargassum wightii Greville has been reported to possess α-D-Glucosidase inhibitory activity. The Present Study revealed as the presence of Phenol crystals, Sulphated polysaccharides and Starch granules in both brown algae.