This report provides guidance how to test efficacy of articles or material treated with biocides. There are two major groups: The first where the treatment is intended to protect the article itself. To prove efficacy, the material/article has to be tested against an untreated variant. In the second group, the treatment is intended to introduce new properties, e.g. to provide hygienic or insect repellency-functions. The problem which the treatment is intended to solve needs to be shown on the untreated article under normal conditions of use. This way, the benefit of the treatment can be shown.