Signs of exsiccation are to be found in almost every fourth acutely ill patient admitted to the geriatric department. The major clinical signs are those associated with reduced general condition, together with somnolence, possibly agitation, oliguria, dry skin, orthostatic hypotension, and a tendency to be bedridden. In such cases, subcutaneous infusion is a simple-to-apply and for the patient stress-free, largely pain-free possibility for fluid replacement. Properly applied and with account being taken of the contraindications--in particular emergency situations, decompensated cardiac insufficiency and severe coagulation disturbances--the risks of s.c. infusion are negligible.