Thoughts control the body. Depending on their orientation, they may have a healing or a morbid effect. Mental processes, associated with feelings and physical mechanisms, control placebo and nocebo effects. They are scientifically proven by numerous studies and it is possible to show them psychoneuroendocrinologically. Both effects can play an important role in the clinical course and in the outcome of therapies. The positive consequence, for instance pain relief, is characteristic for the placebo effect and the negative consequence, such as the adverse side effect, is a typical sign of the nocebo effect. Nursing staff can benefit from the knowledge about factors, which contribute to the positive outcome of the therapy, such as positive expectation, positive previous experience and a trusting relationship, to increase their therapeutic efficacy. The recognition of factors which hinder the effect, for example a negative expectation, a negative impression of previous experience, anxiety and distrust, can also be used by nursing staff to prevent nocebo effects. In addition, the work reveals mistakes in verbal and non-verbal communication and provides ways to activate the self-healing power of the patients, for example the mindfulness meditation and an optimistic view of life.