Patch test screening of patients with suspected contact dermatitis can be greatly simplified by testing with mixtures instead of single chemicals. Topical medicaments, rubber additives, and certain antiseptics were found to be suitable for combining in mixtures. However, combinations of metallic salts and other relatively irritating substances were not feasible. The use of mixtures permits patch test screening of many compounds with a limited number of patch tests. Patch test screening with mixtures is sufficiently rapid to be used by busy practicing dermatologists.