Reference is made to the picture observed in two patients with flaccid tetraparesis, severe hypopotassaemia, and myoglobinuric muscle necrosis (hypokalaemic myopathy). Recent onset of hypertension was a feature of both cases. Initially, however, no reason could be assigned for this, nor for the massive loss of potassium. Numerous investigations in the first case (and relatively quick verification in the second) incriminated a steroid, 9-alpha-fluoroprednisolone acetate, in a nasal spray. This has often been reported as the cause of an iatrogenic syndrome due to excess of mineral corticoids, with hypertension, hypokalaemia and alkalosis, suppression of plasma renin activity, and reduction of blood and urinary aldosterone, all of which were observed in these two patients. Withdrawal of the drug and treatment with potassium chloride led to relatively rapid normalisation of the serum electrolytes. Recovery of muscle strength took place after about 20 days, almost at the same time as the normalisation of muscle enzymes. Hypertension, on the other hand, regressed slowly. The nexus between chronic use of the spray and the occurrence of hypokalaemic muscle necrosis is examined in detail. Stress is laid on the importance of specific investigation of the prior use of intranasal steroids in the differentiation of muscle disturbances due to potassium depletion.