 Cyanobacteria, commonly known as blue-green algae, are one of the earliest forms of life on Earth and play a key role in the evolution of our atmosphere. These microorganisms can thrive in utrophic environments, which are often caused by human activity, leading to the formation of cyanobacterial blooms. These blooms can be harmful to both humans and animals, producing toxins that can cause poisoning and even lead to more serious health issues like cancer. However, some cyanobacterial strains have shown promise in treating certain types of cancer, suggesting that further research could yield beneficial applications. This article was authored by Gillian Zanchit and Eduardo C. Oliveira Filio.