Currently, the pharmaceutical industry is one of the most developing and dynamic sectors of the global economy. Existing methods of wastewater treatment do not always allow the complete removal of pharmacological preparations, which leads to the fact that these substances enter water resources and can have a negative impact on ecosystems and human health. Due to the increase in water pollution with pharmacological preparations, there is a need for more in-depth research in this area. Assessment of the level of contamination with pharmacological substances in the wastewater of megacities is an important aspect of environmental protection and public health. The purpose of this research work is to evaluate pharmacological pollutants in the wastewater of megacities. This study is aimed at identifying APIs (active pharmaceutical ingredients) that are most likely to have a negative impact on the environment in Kazakhstan. To analyze the content of Amoxicillin, Clarithromycin, Ofloxacin, Ciprofloxacin, Atenolol, Metoprolol, Propranolol, Paracetamol, Ibuprofen, Diclofenac, Cabramazepine and other medicinal substances, standards of these substances were added to the wastewater sample and analyzed by the HPLC-MS method. As a result of this research work, information was obtained on the current level of contamination with pharmacological substances in the wastewater of megacities and their impact on ecosystems and human health. The results of the study can be used to develop measures to reduce pollution and conserve water resources for future generations.