Histamine poisoning due to inhalation and skin contact with fish products is rarely described in the literature. This study presents a case of occupational histamine poisoning by spoiled fish flour via inhalation, skin and eye contact. Shipments of fish flour transported in black or blue bags, depending on the source, were handled by 20 harbour workers. Ten workers handling blue bags developed allergy-like skin, eye, gastrointestinal, respiratory and cardiac symptoms within 30 min. Workers handling black bags were symptom-free, except for minimal eye irritation. After consultation with the Poison Control Centre histamine poisoning was suspected. The histamine content, as determined by thin-layer chromatography, was 10-fold higher in samples from the blue than from the black bags (510 mg/100 g flour compared with 50 mg/100 g flour, respectively). Part of the shipment was labelled as hazardous for human health with permission for further usage only under specific personal protective measures. It is suggested that the highest permissible levels of histamine in fish flour and similar products should be set and legally adopted.