Forty-six different foods eaten by six healthy male volunteers were investigated as potential sources of the aliphatic secondary amine, dimethylamine. None that were representatives from the fruit and vegetable, meat, dairy and grain produce categories afforded any measurable elevation in urinary dimethylamine output following ingestion. All of the statistically significant increases occurred after consumption of fish and seafoods. However, within this category a wide variation was observed. The highest values were obtained for coley, squid and whiting with cod, haddock, sardine, skate and swordfish also producing substantial increases. Freshwater trout, plaice and prawns gave no discernable effect. It seems that not all fish and seafoods may be treated equally with regards to human dimethylamine exposure and that the situation is more complicated than at first appears.