Algae are aquatic plants that lack the leaves, stem, roots, vascular systems, and sexual organs of the higher plants. The current application of chemical compounds isolated from diverse classes of algae is enormous. Since 1975, three areas of research in aquatic natural products were emerged: toxins, byproducts and chemical ecology. Over 15,000 novel compounds were chemically determined. Focusing on bio-products, recent trends in drug research from natural sources suggested that algae are a promising group to furnish novel biochemically active substances, algae also contain multitude of bioactive compounds that might have antioxidant, antibacterial, antiviral, anticarcinogenic, etc. properties. Some of them are outlined later due to their special interest as possible functional ingredients.