Consumption of antithrombotic drugs is constantly increasing due to the growing incidence of thromboembolism and cardiovascular diseases. Undergoing antithrombotic therapy are mostly elderly patients, who are a high-risk group of patients, more liable to negative effe cts of drugs, due to physiological changes associated with the aging process, the presence of other chronic diseases and polypharmacy. Antithrombotics - group B01 which consists of 19 generic (names) drugs registrated in Croatia, has a total number of 306 clinically significant interactions in accordance with AHFS first data bank: 73% of them are moderate, 26% are severe, while just 1 % or only two of them have the 1 st level of clinical importance, when the synchronous appliance of these drugs is contraindicated. 63% of overall interactions of this drug g roup are interactions between antithrombotics and antithrombotics with NSAID, which can result in increased risk of bleeding. Most of these interactions are, according to mechanism of action, pharmacodynarnic, sinergistic by nature. These interactions have a special significance due to increasing number of prescriptions for combinations of these drugs in prophylaxis and therapy of various cardiovascular diseases. War fin has the largest number of interactions (29%) mostly due to its specific pharmacokinetic parameters and deserves a special attention. Besides drugs, certain herbal remedies, some of which are very popular (Gingko biloba, St. John's wort, Ginseng), can also interact with antithrombotics. Considering wide consumption, availability, long-lasting therapy and risks linked with certain characteristics of drugs as well as patients, knowledge ofantithrombotic drug interactions is very important for predicting and av oiding their occurence and consequences. lntervening in time we can contribute to the efficiency of therapy as well as the patient safety. The necessity of broad ening the knowledge and of being aquainted with the !atest research in this field of pharmacotherapy seems to be unquestionable_