The surface waters contaminated with cyanobacteria, which are utilized for drinking, irrigation, and recreational purposes, poses a potential hazard to population health, as well as domestic animals and wildlife. Due to the observed trends of rising temperatures and the increased levels of nutrient pollution in surface waters, the occurrence of marine biotoxins is a growing concern worldwide. Paralytic shellfish toxins (PST), described in marine invertebrates, humans, and bacteria are a large neurotoxic group consisting of saxitoxin (STX) and its about 57 derivatives. It is produced by eukaryotic dinoflagellates and prokaryotic cyanobacteria. Paralytic shellfish toxicity is mostly associated with seafood consumption. STXs effectively inhibit the distribution of nerve impulses, and the function of sodium channels located on the nerve cells. As a result, the activation of muscular activity is inhibited, leading to respiratory paralysis. Understanding of the conversion of PST into less toxic derivatives and its degradation both chemically and enzymatically is important for the detoxification of eutrophied water resources and consumed seafood. Since some PSTs have been identified as having pharmaceutical potential, studies on elucidating the STX biosynthesis genes in cyanobacteria will guide research in order to better understand the pharmaceutical potential of these alkaloids and to elucidate their structures.