saxitoxin

Saxitoxin is a potent neurotoxin, chemically represented as C₁₀H₁₇N₇O₄·2HCl. It originates from certain dinoflagellates, such as those in the genera Alexandrium, Gymnodinium, and Pyrodinium, which are often found in red tides. These microorganisms produce saxitoxin, which can accumulate in shellfish that consume them, rendering the shellfish toxic to humans.12

Ingesting shellfish contaminated with saxitoxin can lead to paralytic shellfish poisoning. Symptoms include a tingling and numbness of the lips, tongue, and face, which can spread to the rest of the body. This can progress to weakness, muscular paralysis, and in severe cases, can be fatal. There is no specific antidote for saxitoxin poisoning.2