Cyanobacteria are photosynthetic prokaryotes and major contributors to global biogeochemical cycles. They possess powerful biological activity, high adaptability to extreme environment, rapid growth rate and genetic editability. Here, we review cyanobacteria with focus on their application in environmental pollution and biomedicine. Cyanobacteria can be used for pollutant removal, biofuel and biochar production, template for drug discovery, hypoxia-related disease therapy, anticancer, antiviral, antibacterial, antioxidant and antifibrotic. Spiral-shaped cyanobacteria are excellent carriers for...