Paralytic shellfish poisoning, in some areas called mussel poisoning, is a disease caused by eating shellfish such as clams or mussels that have been feeding on a poisonous marine dinoflagellate. Symptoms of the disease usually are apparent shortly after eating poisonous shellfish and begin with a tingling sensation and numbness in the lips, tongue, and finger tips followed by numbness in the legs, arms, and neck with general muscular incoordination. A feeling of lightness as though floating on air is often described by the afflicted persons. Other associated symptoms are dizziness, weakness, drowsiness, incoherence, and headache. As the illness progresses, respiratory distress and muscular paralysis become more and more severe. These poisons cause sickness and death by blocking specifically the sodium channels in nerve and muscle cell membranes.2,4 The passage of sodium ions through these membranes into the cells is essential for the passage of an impulse in a normal manner along a nerve and muscle fiber. The diaphragm apparently is most sensitive to the poisons and death results from respiratory paralysis within 2 to 24 hr depending upon the magnitude of the dose. If one survives 24 hr, the prognosis is good and normal functions are regained within a few days. There is no effective antidote for shellfish poisoning and patients should be given medical treatment without delay. Artificial respiration is the recommended method of treatment if respiratory distress is apparent. The amount of poison to cause illness from eating poisonous shellfish may be as little as 1 mg and death may result from as little as 1 to 4 mg. This amount of poison could be contained in one small mussel.