An adequate antioxidant keep which is usually present in a vegetarian diet is associated with higher life expectancy; several studies hold the hypothesis that lipid oxidation products ingested with food or produced endogenously represent a health risk. It is well established that free radicals and reactive oxygen species are continuously produced in vivo, the primary products of free radical oxidation undergo rapid and spontaneous fragmentation. Some have significant lethal potential. The peroxidations of lipids have gained significance in recent times because of its implication in the causation of a number of diseases. On the basis of the results obtained in vitro assays of hydroalcoholic extract of gracilaria edulis such as Scavenging of ABTS radical method, Scavenging of superoxide radical by alkaline DMSO method, Scavenging of hydrogen peroxide and DPPH assay shows a significant source of natural antioxidant, which might be accommodating in preventing the progress of various oxidative stresses.