On reviewing the literature, the meaning of risk factors causing stroke as well as their therapy or elimination as an effective prevention of cerebro-vascular disease is pointed out. Hypertension increases the risk of apoplexy by the fourfold, with regard to the diastolic values of blood pressure by the fivefold up to the tenfold. Consistent therapy of hypertension decreases significantly the incidence of cerebral apoplectic attacks. Manifested diabetes mellitus and even reduced glucose tolerance raise the risk of stroke by the threefold, even though factors frequently associated with diabetes (hypertension, overweight, hyperlipoidaemia) are taken into consideration. Hyperlipidaemia, hypercholesteraemia, and hypertriglyceridaemia stipulate an increase of the incidence of stroke by the twofold to the threefold. Morbidity rate rises if these abnormalities coincide with further risk factors (hypertension, reduced glucose tolerance, smoking cigarettes, hypertrophy of left heart-ECG), up to the sixfold. Nicotine consumption alone increases the risk of cerebral apoplectic attacks in relation to age, by the threefold up to the fivefold. In combination with the use of hormonal contraceptive drugs, the risk of morbidity rate in women rises to the sevenfold. Overweight of more than 30% aggravates twice the risk of stroke. Heart diseases of different kind increase the risk of apoplectic attacks by the twofold; in combination with hypertension by the fivefold. The intake of oral contraceptive drugs causes an increase of cerebral thrombo-embolic attacks by the threefold up to the fivefold, where by a relation to the content of oestrogen and to the disturbances of haemorheology is proven.(ABSTRACT TRUNCATED AT 250 WORDS)