The symptoms of palytoxin poisoning and how quickly they appear depend partially on how much and through what route one has been exposed, e.g. if the poison has been inhaled or if the exposure has happened via skin.
In some non-lethal cases the symptoms in people have appeared in 6–8 hours after inhalation or skin exposure, and have lasted for 1–2 days. In different animals the symptoms have appeared in 30–60 minutes after intravenous injection and after 4 hours of eye-exposure.
The most common complication of severe palytoxin poisoning is rhabdomyolysis. This involves skeletal muscle breakdown and the leakage of intracellular contents into the blood. Other symptoms in humans are bitter/metallic taste, abdominal cramps, nausea, vomiting, diarrhea, mild to acute lethargy, tingling, slow heart rate, kidney failure, impairment of sensation, muscle spasms, tremor myalgia, cyanosis, and respiratory distress. In lethal cases palytoxin usually causes death by cardiac arrest via myocardial injury.
Exposure to aerosols of palytoxin analogue ovatoxin-a have resulted mainly in respiratory illness. Other symptoms caused by these aerosols included fever associated with serious respiratory disturbances, such as bronchoconstriction, mild dyspnea, and wheezes, while conjunctivitis was observed in some cases.
Clupeotoxism, poisoning after consuming clupeoid fish, is also suggested to be caused by palytoxin. Neurological and gastrointestinal disturbances are associated with clupeotoxism. Haff disease might be related to palytoxin and is characterized by rhabdomyolysis and gastrointestinal problems. In addition to ciguatoxin, palytoxin could be related to ciguatera seafood poisoning in some cases and thus give rise to a number of symptoms in this poisoning.