[Double blind test with a protective ointment (Ivosin) on the hands of cement workers].

56 builder's labourers manipulating lime cement applied a protective cream on their hands and 57 used a placebo in a double blind test of two months' duration. The labourers, the doctors who surveyed the condition of their hands, and the statistician who analyzed the results knew only that one cream had a blue label, and the other a green one. Before and after the test, the presence or the absence of certain symptoms on the hands were objectively examined, while the subjective opinion of the labourers was registered at the end of the test. As usual in tests of that kind, the great majority of the labourers (more than 75%) were satisfied, 62% of them acknowledged an improvement. That percentage justified a comparative double-blind study that revealed a much higher quota (86% of the test persons) of satisfaction among the labourers treated with Ivosin than in the placebo group (66%). That difference was statistically significant. On the other hand, no objective difference could be revealed between the two groups. It was impossible to discover among the symptoms studied, any objective cause of that subjective difference.