Recently, microalgae cultivation for different applications, including the production of nutritional and pharmaceutical active compounds has received increasing attention. Among the different genera, Spirulina (Arthrospira sp.) is one of the most promising blue-green microalgae (Cyanophyta) because it is rich in antioxidants, essential amino acids (EAAs), minerals, proteins, polyunsaturated fatty acids and vitamins. It has a high protein content (60-70% of the dry weight), which is a complete protein, i.e. containing all EAAs. Therefore, Spirulina is currently a commercial product with high nutritional value and also a significant source of complementary and alternative medicine. The objective of the present work was to review the pharmaceutical and therapeutic applications of Spirulina, especially its antioxidant, anti-inflammatory, anti-cancer, anti-microbial, anti-diabetic, anti-obesity and anti-toxicity properties. The results were obtained from experiments in the literature performed in vitro and in vivo using experimental animals. The main reported active ingredients in Spirulina include phycocyanin, tocopherol, β-carotene, caffeic acids and chlorogenic acid, which showed individual or synergetic effects. In addition, the present review discusses the future perspectives of genetically modified Spirulina as a source for industrial products while producing valuable biomass photoautotrophically. Furthermore, the consequent environmental impacts of large-scale cultivation of Spirulina are discussed.