Normally, the number of platelets in a healthy adult is in the range of 150-320 x 10⁹. A condition in which their number falls below 150x10⁹ is called thrombocytopenia. It can be both associated with a violation of the process of platelet formation in the bone marrow (in particular, with aplastic anemia, hemoblastosis, thrombocytopenic purpura), and be a concomitant pathology, for example, be a consequence of drug treatment of a number of somatic diseases. In the pathogenesis of thrombocytopenia, three main directions are distinguished: a decrease in platelet production, an acceleration of their decay and a violation of the distribution of the platelet pool with their sequestration in the spleen. Most often, drug thrombocytopenia develops against the background of the use of cytostatics, chloramphenicol, antithyroid drugs, NSAIDs. The decrease in the number of platelets can also be influenced by the regular use of alcohol, some infectious diseases, and immunodeficiency states. The main clinical manifestation of thrombocytopenia is hemorrhagic syndrome, proceeding as petechial rashes or ecchymosis, however, in some cases, clinical manifestations may be absent, and then the diagnosis is made on the basis of a clinical blood test. Treatment of thrombocytopenia is carried out taking into account the etiological factor that caused it.