The objective of the study was to obtain further experience on the applicability of 2 tests for clinical assessment of formaldehyde exposure. About 1300 products brought in by caosecutive formaldehyde-sensitive eczema patients during a 2-year period were tested with both the chromotropic acid test and the acetylacetone test. The chromotropic acid test was modified by including a 2nd reading after 2 days. The outcome was identical for about 90% of the products, and 74% of he products that were positive on day 2 were also positive on day 2. For products analyzed with both the chromotropic acid test (day 2 readings) and the acetylacetone test. About 80% gave identical results. Positive reactions were frequently found for hair shampoo, creams and lotions, soap and skin cleansers. Make-up and dishing liquids. The samples causing discolouration or problems in the tests were mostly concentrated in specific product categories. Very few products caused problems in both test methods. Thus, the most convenient test can be used as the 1st choice and, for product categories causing discolouration or problems with a specific test, the other test method can be used.