In the clinical study presented etiroxate hydrochloride was shown to have a pronounced cholesterol-lowering effect. The percentage decrease of cholesterol values during treatment with 40 mg daily was significantly greater than that during 20 mg daily. The mean decrease was 41.2% in patients with initial cholesterol values greater than 350 mg/100 ml and 25.9% in those with initial values less than 350 mg/100 ml. However, it must be emphasized that 20 mg daily also produced a mean decrease in the serum cholesterol values of more than 20%. With initial values below 350 mg/100 ml the difference in the cholesterol decrease between the two dosage groups is not therapeutically relevant. Therefore treatment in patients with hypercholesterolaemia or type IIa and IIb hyperlipoproteinaemia should begin with 20 mg daily. The results suggest that raising the dose to 40 mg daily is only appropriate when a satisfactory decrease in serum cholesterol cannot be achieved with 20 mg daily. The preparation does not consistently lower the triglycerides, but in some cases the effect is very pronounced. A careful diagnosis must be made before administering etiroxate hydrochloride and continuous medical supervision and checks for side-effects are necessary throughout treatment.