The chamber scarification test is a predictive human skin irritation test developed to rank the irritation potential of products and ingredients meant for repealed use on normal and diseased skin. 12 products or ingredients can he tested simultaneously on the forearm skin of each volunteer. The test combines with the procedure scratching of the skin at each test site and subsequent closed patch tests with the products, repeated daily for 3 days. The test is performed on groups of human volunteers: a skin irritant substance or products is included in each lest as a positive control, and a compound with low irritant potential as a negative control, to obtain relative characterization of the irritant potential of the unknown products. The outcome of tests with a positive and negative control product used repeatedly in 13 chamber scarification tests over a 7–year period is reported, and shows high reproducibility of the test. Further intra‐individual variation in skin reaction to the 2 control products in 26 volunteers, who participated 2x, is shown, which supports the conclusion that the chamber scarification lest is a useful short‐term human skin irritation test with high reproducibility.