Drugs that inhibit Bruton's tyrosine kinase (BTK), which is an enzyme that promotes malignant proliferation of B lymphocytes, have been discovered for the treatment of different types of B lymphocyte lymphoma. Inhibition of this enzyme blocks the signaling pathways that are important in the development of malignant changes. This group of drugs includes ibrutinib, acalabrutinib and zanubrutinib. This thesis provides an analysis of all suspected reports of adverse reactions to drugs that inhibit BTK, which were reported to the Agency for Medicinal Products and Medical Devices (HALMED) in the period from January 1, 2015 to December 31, 2021. Reports were analyzed considering: gender, age, reporter qualification, seriousness, seriousness criteria, Medical Dictionary of Regulatory Affairs (MedDRA) organ system classification, the most common adverse reactions and concomitant medications. In the observed period, 123 reports were received with a total of 220 adverse reactions. The highest number of reports was recorded for males (65.9%) and for the age group 65 to 74 years (28.5%). The highest number of adverse reactions was reported by doctors, and a large number of them were assessed as serious (69.9%). Out of a total of 220 adverse reactions, the highest number of them according to the classification of organ systems belongs to SOC infections and infestations (17.7%), SOC disorders of the skin and subcutaneous tissue (10%) and SOC heart disorders (8.2%) and the most commonly reported were atrial fibrillation, sepsis and pneumonia. The data in this thesis are in accordance with the data at European and global level. The number of reports of suspected adverse reactions, both for drugs that inhibit BTK and for other drugs, is higher every year. This is the result of the quality work of HALMED and other world agencies, to raise awareness on the importance of reporting suspected adverse drug reactions. Further efforts are needed to improve the safety of BTK-inhibiting drugs to ensure safe and effective treatment of patients with as few adverse reactions as possible.