A national database on chemical products (the Danish Product Register (PROBAS] was searched for products containing selected contact allergens. As of June 1990, a total of 47,400 products were registered in PROBAS. About 27,800 of these were fully computerized. A list of 43 allergens was established, based on the European standard patch test series, substances classified "May cause sensitization by skin contact", text books on contact dermatitis, and clinical experience. The number of products in which each of these allergens was registered varied from 30 to more than 1300. Formaldehyde was registered in all product categories included in the study. Benzyl alcohol, stearic acid, epoxy compounds, diethylenetriamine and butylated hydroxytoluene were registered in more than half of the product categories. Paints/lacquers and hardeners for two-component products (paints, glues, fillers, etc.), cleaning agents, binders, adhesives/glues and toiletries made up the most frequently registered product categories for the allergens listed. The possibilities and limitations of database information on chemical products are discussed.