Placebo effect

A placebo is a physiologically inert substance used as a medicinal drug to reassure a patient. A Placebo effect is a positive therapeutic effect claimed by a patient after receiving a placebo. Generally, the term "placebo effect" is a positive therapeutic effect not only medicine drug, but for example from some kind of radiation, conversation, laser therapy, etc.
An efficiency of the Placebo depends on patient’s suggestibility and external circumstances of the treatment. Bigger and brighter pills have the greater effect. Placebo injection works better than a placebo tablet. Sometimes doctors deliberately prescribe placebos to patients who prone to autosuggestion symptoms of sick. In this case, they avoid unnecessary drug therapy and multiple drug complications. The positive effect of homeopathic is also explained by placebo effect. Placebo effect may be explained by as a result of suggestion the patient's brain begins developing substances with appropriate action, including endorphins, which in effect partially replacing the action of the drug. The second factor that ensures the effectiveness of placebos is increasing general immunity of human.
The placebo effect makes it more difficult to evaluate new treatments. I think all clinical trials should be double blinded so that the researchers also do not know which subjects are receiving the active or placebo treatment.