Most of us have heard about the placebo effect - the healing effect on the body of completely harmless pills or powders, which, however, patients are informed by the doctor that they are a new revolutionary drug. The placebo effect is medically proven and works in up to 80% of cases of application. Interestingly, the placebo effect is effective in almost all diseases. Proven cures for bronchitis, pneumonia, ulcers, regulates blood pressure, cancer. But the placebo effect has its dark side. The power that the mind-body connection has can heal, but it can also hurt.