Abstract Annatto extracts contained in the pericarp of the fruit Bixa orellana are extracted by several methods. Commercial preparations consist of solutions or suspensions of the pigment in vegetable oil or as a water-soluble form in dilute alkaline solution. The major pigment of the fruit is cis -bixin (80%+) with smaller amounts of other carotenoids. Cis -bixin, on heating in solution, is partially converted into the trans isomer and a yellow degradation product. The extent of the degradation is dependent on the temperature and the duration of the heating process and governs the red/yellow balance. The dicarboxylic acid salts of cis -norbixin and trans -norbixin occur in heated alkaline solutions. The current toxicological situation of annatto describes recent results of studies at the Unilever Research Laboratory at Colworth House, Bedford.