Placebo therapy is frequently effective and is not a "non-therapy". Placebo effects can be shown only by direct comparison with a "non-therapy". A placebo therapy is frequently accompanied by adverse drug reactions (ADRs) just as a verum therapy. Placebo ADRs are frequently illness- and verum-specific. Effects and ADRs of placebo therapy must be known, to judge the effect of verum medication in controlled clinical trials. The mechanisms of placebo effects are manifold (e.g. endorphine release, conditioned learning). Since placebo therapy outside of evidence-based medicine (use of drugs without proven efficacy = pseudoplacebos) may potentially also cause serious side effects, the use may not only be useless but also harmful.