BACKGROUND: Serum carotenoids consist of a variety of different compounds. Xanthoderma may result from an increased concentration of any of the carotenoids. METHODS AND RESULTS: High-performance liquid chromatography of serum carotenoids shows that a normal chromatogram contains mainly beta-carotene, lutein and lycopene. Serum alpha- and beta-carotene, beta-cryptoxanthin, lycopene, lutein and zeaxanthin were found to be increased in the investigation of hypercarotenaemia. CONCLUSION: Patients presenting with possible xanthoderma should have a dietary history taken and serum sent for carotenoid analysis.