Housing & Human Services locations in Boulder & Longmont are closed until Feb. 13. Call 303-441-1000, text 303-441-1069

Scombroid Fish Poisoning
tuna fish

Scombroid Fish Poisoning

Scombroid, or histamine poisoning, is caused by bacterial spoilage of certain finfish, such as tuna, mackerel, bonito, skipjack, mahi-mahi, and bluefish.


Symptoms begin within 2 minutes to 2 hours after eating the fish, and may include rash, diarrhea, flushing of the face, and sweating, headache, dizziness, and vomiting. In addition, individuals may experience burning or swelling of the mouth, abdominal pain, or a metallic taste.

Most people experience mild symptoms which should resolve on their own within 12 hours. Symptoms may be more severe in patients taking certain medications that slow the breakdown of histamine by their liver, such as isoniazide and doxycycline.


After capture, fish undergo bacterial decomposition in which bacteria break down fish proteins, in turn allowing byproducts, such as histamine, to build up. Eating spoiled fish that have high levels of these histamines can cause human illness.


Diagnosis is based on symptoms and a history of recently eating a particular kind of seafood.


Treatment is generally unnecessary, but antihistamines or epinephrine may be needed in certain instances.


Always keep seafood refrigerated or on ice to prevent spoilage. Take precautions while traveling and limit your intake of tuna, mackerel, bonito, skipjack, mahi-mahi, and bluefish. Cooking spoiled or toxic seafood will NOT keep you safe, as Scombroid is NOT destroyed by the cooking process.

For more information:

Contact Us

Food Safety Program

Main: 303-441-1564
Submit a question


3450 Broadway
Map & Directions
Hours: 8 a.m. - 4:30 p.m. M-F