Diuretics are among the most frequently prescribed substances in elderly patients, but they are also associated with the highest incidence of adverse effects in this group of patients. Xipamide is a sulfonamide-like diuretic whose action does not depend on transtubular secretion. This characteristic makes it suitable for situations in which the kidney is highly sodium avid. Because of the potency of this substance the risk of adverse reactions like electrolyte disorders or hypovolemia is increased as well. We report seven patients (age 65-85) admitted to the emergency room of the University Hospital of Innsbruck between 1998 and 2002 who had developed serious adverse reactions upon initiation of treatment with xipamide as an additional diuretic. Six of these patients had received combinations with loop diuretics. The disturbances observed were hyponatremia (lowest value 108 mmol/l), hypokalemia (lowest value 1.5 mmol/l) and prerenal azotemia (highest serum urea 269 mg/dl, highest serum creatinine 5.13). With the exception of diuretic resistance in severe heart failure or renal insufficiency a combination therapy of xipamide with a second diuretic appears to be associated with an unnecessarily high risk of serious adverse reactions and thus should be avoided. This is especially true for elderly patients.