Background - On November 26, 2010, several cases of scombrotoxin poisoning were detected among French military personnel stationed in Dakar, Senegal. This food poisoning, caused by high levels of histamine in the food consumed, is often mistaken for an allergic reaction. Method - A case-control study was conducted among the 237 individuals who ate the meal in question to confirm the nature and identify the source of this poisoning. Bacteriological and chemical analyses of the meal in question were performed. Results - The epidemiological investigation identified 71 cases. Among the other meal recipients, 78 controls were sampled. The typical symptoms of scombrotoxin poisoning were observed in the cases: erythema (85.9%), headache (83.1%), weak and rapid pulse (59.1%), and diarrhea (47.9%). These symptoms appeared within a few minutes to 3 hours after the meal. Most patients recovered quickly with the administration of antihistamines and/or symptomatic treatment. Tuna was the only food significantly associated with the illness (OR 36.3; 95% CI [6.3–210.0]), with the risk of illness increasing with the amount of tuna consumed. No contamination by pathogenic bacteria was detected in the control meal. In contrast, the histamine concentration measured in the tuna sample was 4,900 mg/kg, which is 50 times the limit authorized by European regulations. Conclusion - This mass histamine food poisoning outbreak is unique due to the high number of people affected and the definitive diagnosis provided by chemical analyses of the food responsible for the poisoning. (R.A.)