In 121 patients, 26 substances of a standard test battery were applied symmetrically on both sides of the upper back. The Finn chamber on Scanpor was the test system used, the final reading being taken on day 3 or 4. Of 166 tests, 131 were positive on both sides. Test substances and patients age had no influence. In comparison with the results in the literature, ours show a good reproducibility of 78.9%. Doubtful reactions (?+) were difficult to evaluate. These reactions deserve future research.