High performance liquid chromatography has acquired great importance recently for an analysis of the drugs in biological fluids of the body. Phase inversion sorbents are particularly widely used today. However, the use of ion-exchange sorbents is fairly promising for an analysis of the drugs capable of ionizing in an aqueous solution. The authors illustrate the use of the latter ones for determination in the blood, urine and saliva of man of a number of the cardiologic drugs (etmozine, nonachlazine, verapamil, prazosin, propranolol, nadolol). Ion-exchange sorbents make it possible to attain better results than inverse phase ones, since they retain the drugs selectively and do not retain the endogenous substances of lipid nature. As regards verapamil, prazosin and propranolol, the unchanged drug and polar metabolites could be determined jointly, with such a determination being not feasible with the use of phase inversion sorbents. Separation of the diastereoisomers of nadolol was achieved in the blood and urine of patients who received the drug.