Marine resources have been used for many years because of their bioactive properties. Benthic macroalgae have recently gained significant importance due to their cosmopolitan distribution, renewable nature, and wide range of applications. Harvest of wild populations, along with simple breeding techniques that are largely evolved in Asian countries, has propeled seaweeds to become the subject of numerous biomedical research studies and a perspective raw material for new functional compounds. The great diversity of marine habitats provides a variety of opportunities for thriving and adaptation of seaweeds. Benthic macroalgae are multicellular organisms are the primary producers. Their adaptation in the environment depends on temperature, light availability, turbidity, salinity, pigmentation, quality of substrate, fluxes, depth and other environmental conditions. The frequency and abundance of the amorphous portion of cell (sulfated polysaccharides) makes this resource economically important. The colloidal properties of these high molecular weight polysaccharides, also known as phycocolloids, have found application in numerous industries, and more recently in biomedicine. Extraction products of the most important hydrocolloids, agar, carrageenan and alginates are found in many commercially available products on the market. Hydrocolloids are not only ingredients in food, but show various bioactive properties and physiological effects that have great benefit for human health. They have been used in various traditional medicine preparations since early history, while modern science has advanced understandings of physiological effect of these biogenic compounds and their potential applications in biomedicine. Their importance is greatest in food and phycocolloid industries. The use of seaweeds in agriculture, cosmetics, fuel production and ecology has recently been a rapidly growing research sector. Likewise, modern scientific discoveries contribute to a better understanding of bioactive properties, and biosynthetic pathways of their natural products.