Cyanobacteria are simple, photosynthetic, prokaryotic blue-green algae. They can thrive in fresh water, terrestrial, glacial, aerial, brackish and marine regions. Cyanobacteria have been exploited in recent decades due to the presence of compounds with potential activity like pigments, vitamins, proteins, carbohydrates, minerals etc. These potential compounds have valuable applications as pharmaceuticals, nutraceuticals and cosmeceuticals and also as health supplements. This review focuses on the phycocyanin pigment of cyanobacteria and its pharmaceutical applications. Phycocyanin is a blue-colored pigment protein that is abundant in cyanobacteria. Phycocyanin is exploited due to its antioxidant properties, antidiabetic, anti-inflammatory and anticancer activity. This pigment can be used as a nutrient supplement in order to treat age-related diseases and other oxidative stress-related diseases.