• Saxitoxin (STX) is a potent marine biotoxin
• STX and its analogs are synthesized in both marine and freshwater environments by dinoflagellates of the genus Alexandrium
• Saxitoxin enters the water column as a by-product of massive dinoflagellate proliferation and aggregation
• Saxitoxin is an inhibitory neurotoxin that induces flaccid paralysis by actively suppressing excitation of neuronal impulses