Gas liquid chromatography was used to study the spectrum of short-chain fatty acids (SCFA) in the serum and epidermal corneal layers of abnormal and apparently healthy skin areas in patients with psoriatic disease on an exacerbation and at a progressive stage. Significantly lower SCFA levels were detected in both psoriatic and intact areas, with derangements being mostly manifested in the papulae. There were heterodirectional serum volatile fatty acid spectrum changes that were characterized by a rise in the concentrations of isobutyrate, valeriate, and capronate and by a decrease in the proportion of acetate and propionate.