What Is Scombroid Poisoning?
The CDC says scombroid is caused by eating fish that contain high levels of histamine and other scombrotoxins, formed when improper handling and storage lets bacteria convert histidine in the fish to histamine. It says that conversion happens best at 20 to 30 degrees Celsius, 68 to 86 degrees Fahrenheit, which typically occurs in fish not promptly refrigerated or frozen after capture.
Fish typically associated with scombroid have naturally high histidine levels and include amberjack, anchovies, bluefish, herring, mackerel, mahi mahi, marlin, sardines and tuna, the CDC says. Once the histamine has formed, it is not destroyed by gastric acid or by canning, cooking, freezing, pickling, salting or smoking.
The CDC says scombroid poisoning resembles an acute allergic reaction and usually appears 10 to 60 minutes after eating contaminated fish, with abdominal cramps and diarrhea, blurred vision, flushing of the face and upper body resembling sunburn, severe headaches, itching and palpitations. The FDA's seafood guidance lists similar symptoms lasting from 12 hours to a few days, sets a guidance level of 50 parts per million histamine in the edible portion of fish, and explains that if 50 ppm is found in one section of a fish or lot, other sections may exceed 500 ppm.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceThe CDC says scombroid is caused by eating fish containing high levels of histamine and other scombrotoxins, formed by bacteria after improper handling and storage. CDC, Yellow Book ↗
- Government sourceThe CDC says the conversion of histidine to histamine occurs best at 20 to 30 degrees Celsius, which typically happens in fish not promptly refrigerated or frozen after capture. CDC, Yellow Book ↗
- Government sourceThe CDC lists amberjack, anchovies, bluefish, herring, mackerel, mahi mahi, marlin, sardines and tuna among fish associated with scombroid, and says histamine is not destroyed by cooking, canning, freezing, salting or smoking. CDC, Yellow Book ↗
- Government sourceThe CDC says scombroid resembles an acute allergic reaction 10 to 60 minutes after eating contaminated fish, with cramps and diarrhea, blurred vision, flushing, severe headaches, itching and palpitations. CDC, Yellow Book ↗
- Government sourceThe FDA sets a guidance level of 50 ppm histamine in the edible portion of fish, and says that if 50 ppm is found in one section of a fish or lot, other sections may exceed 500 ppm. US FDA, Fish and Fishery Products Hazards and Controls Guidance ↗
- Government sourceThe FDA says scombrotoxin poisoning symptoms usually occur within a few minutes to a few hours of eating the fish and last from 12 hours to a few days. US FDA, Fish and Fishery Products Hazards and Controls Guidance ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.