This monograph includes five chapters describing spirulina, a biomass of cyanobacteria with strong antioxidant effects and various other health benefits. Chapter One addresses the boosting effect on the immune system by spirulina, exploring its antiviral activity and respective mechanisms. Chapter Two evaluates the neuroprotective effect of spirulina and its aqueous extract in two models of fetal alcohol syndrome in mice. Chapter Three reviews biomolecules of industrial interest with health benefits that can be extracted from spirulina biomass and describes the factors that influence their synthesis as well as their application in food and pharmaceutical industries. Chapter Four provides a broad overview of the various health benefits of spirulina. Finally, Chapter Five describes the beneficial effects of spirulina on conditions including obesity, cardiometabolic disturbances, and immunitary processes.