Abstract: Spirulina (Arthrospira) is a microscopic blue-green algae and it is considered as one of the richest sources of organic nutrients that are making it a good nutritional supplement for human and animal feed worldwide. Spirulina contains good quality proteins, vitamins and minerals in addition to a wide variety of natural carotene and xanthophyll phytopigments. Owing to its unique and impressive nutrient composition, Spirulina is used as a dietary inclusion in a large scale of food products not only to enhance their nutritional qualities but also for therapeutic purposes. On this aspect, many researchers studied the beneficial effects of Spirulina and reported its enhancing potential on the productive and reproductive performance, improving general health as well as lowering the problems of different animal diseases like arthritis, diabetes, anaemia, hypertension and cardiovascular disorders. Other studies have demonstrated that Spirulina possess some promising biological activities such as antitumor, antimicrobial, antiviral, anti-inflammatory, hypocholesterolemic, radio protective and metalloprotective effects. These pharmaceutical and medicinal properties of Spirulina could be attributed to some natural constituents such as phycocyanin, carotene, tocopherols, linolenic acid and phenolic compounds that had been shown to have strong antioxidant properties and powerful scavenging activities against Reactive Oxygen Species (ROS) like superoxide and hydrogen peroxide radicals. This review illustrates the beneficial effects of Arthrospira on poultry, animals and human health and throws the light on its ability to protect the body physiological system against oxidative damage and as nutraceutical and source of potential pharmaceuticals based mainly on the highest levels of evidence available in the literature.