Any medical procedure must be legally authorized by the patient, giving inf
ormed consent. This prerequisite is based on the right to self determinatio
n. Otherwise a medical procedure is considered as physical injury. Thus, th
e way, how a specific procedure is performed, predominantly depends on the
patient's will. The attending physician's duty is to find out this will, wh
ich is especially important when old patients and patients incapable of giv
ing valid consent are involved. Before the procedure the physician has to h
ave a confidential talk with the patient. He has to point out the best trea
tment possible considering the individual circumstances of the patient's li
fe. The physician has to find out, weather the patient is competent to refu
se or consent to treatement. Furthermore the consultation is an opportunity
to diminish the patient's fear and to increase his confidence. The main pr
oblem treating old patients is that they often lack the mental ability for
appreciation of the nature of the situation. One has to differentiate betwe
en the physiological mental decay and dementia or psychiatric diseases. In
these cases a third party consent is necessary.