Because there is no disease condition that can be treated with the administration of anaesthetic medications, the specialty of anaesthesiology does not possess a curative effect in itself. Nevertheless, achieving the state of anaesthesia or the anaesthetic state relies completely on the use of drugs. Drugs used in anaesthesia are very powerful and able to transiently break the most deeply rooted physiological defence mechanisms. Some of the effects induced include lack of consciousness, absence of response to pain, absence of muscle tone, immobility, lack of breathing and dysfunction of the autonomic nervous system, to name just a few. Some of these effects might be considered target or ‘therapeutic effects’, such as unconsciousness, analgesia or immobility, but others are ‘side effects’ that are induced because of the relative low specificity of currently used anaesthetic drugs.