Mixtures of food colour, sucrose and glucose were heated at several temperatures under simulated candy making conditions. Amaranth (128μg/g), sunset yellow FCF (113μg/g) and tartrazine (116μg/g) were found to decompose by up to 25%, 10% and 22% respectively over a temperature range of 120–162°C. The decomposition increased with increasing temperature. The products found as a result of amaranth decomposition corresponded to naphthionic acid and amino‐R‐salt. No increase in intermediates was observed in the candies as a result of the decomposition of sunset yellow FCF and tartrazine during the cooking process. Analytical methodology included sample cleanup with reversed‐phase cartridges (ion‐exchange cartridges for sulphanilic acid) followed by liquid chromatography with ultraviolet absorbance detection. Average recoveries of all compounds studied were 94–100%. A survey of commercial candies for food colour intermediates indicated that no significant increase in their levels above the regulatory limits was found.