Cylindrospermopsin is a toxin produced by certain freshwater algae. It can contaminate drinking water sources during algal blooms, potentially causing liver and kidney damage.

Cylindrospermopsin is produced by certain species of cyanobacteria, commonly known as blue-green algae. It can contaminate drinking water sources when these organisms proliferate in freshwater bodies, forming algal blooms. The toxin is typically measured using advanced laboratory techniques such as liquid chromatography. Climate change and nutrient pollution from agricultural runoff and wastewater contribute to the increasing frequency of cylindrospermopsin-producing algal blooms in water supplies worldwide.