Early occurences of organ damage, mainly in the cardiovascular system, the central nervous system, of the kidney or the retina, are hallmarks of a malign course in arterial hypertension. Peracute hypertensive emergencies can lead to a rapid deterioration of organ functions, a slower development is observed in patients with therapy-resistant forms of arterial hypertension. In the following article we discuss the historical trends in terminology and epidemiology, clinical symptoms, and possible causes for therapy-resistant hypertension. The latter mainly focuses on possible secondary forms of hypertension and on thoughts on therapy-resistance in primary, idiopathic arterial hypertension, as well as on possible therapeutic approaches.