The increase in the amount of pharmaceuticals in the environment is the result of rapid development of medicine and pharmacy, and also the more intensive use of pharmaceuticals. Environmental water systems are the most exposed to contamination with pharmaceuticals. Pharmaceuticals enter the environment via pharmaceutical industry plants, via improper disposal of unused pharmaceutics on landfills, and as metabolites and/or non-metabolised pharmaceutical supstances that are the result of various biological reactions of active pharmaceutical ingredients (API) in the organisms via municipal waste water. The resulting metabolites that are formed this way are a problem for themselves, as they often have less favorable environmental properties than the initial matter, for example they are more toxic and harder or non-biodegradable. Salicylic acid (SA) is the major metabolite of acetylsalicylic acid, known by the commercial name aspirin. SA is also naturally present in some plants as phytohormone, and it is used in the treatment of various skin diseases. Ozonation proved to be an effective way of removing SA from waste and natural water. In this paper the effectiveness of the reference process of direct ozonation, the ozonation as an advanced oxidation process, catalytic ozonation (O3/Fe2+, O3/Mn2+), UV-C ozonation (UV-C/O3) and catalytic ozonation combined with UV-C radiation (UV-C/Fe2+/O3 i UV-C/Mn2+/O3) for mineralization of SA at two different pH values (pH 3 and pH 11) was investigate. According to the results of the NPOC analysis, in comparison with direct and advanced ozonation, a significant acceleration of mineralization was achieved by catalytic processes with and without UV radiation. The catalytic process of UV-C/Fe2+/O3 represents the process with the highest rate of mineralization and it can be described by the zero-order kinetic model with kobs = 74,3 M^-1 min^-1. Subsequently, changes in environmental parameters (COD, BOD5 and acute toxicity on Vibrio fischeri) were monitored in direct ozonation and UV-C/Fe2+/O3 treatment of water loaded with SA, inorganic salts (chlorides, nitrates, phosphates and sulphates) and NOM. The most significant increase of biodegradability in direct ozonation treatment was achieved in the presence of chloride and NOM, while the UV-C/Fe2+/O3 process results in a small, slight increase in biodegradability in all tested matrices. There was a significant decrease in toxicity on V. fischeri in all experiments with direct ozonation experiments, and in all investigated cases with applied UV-C/Fe2+/O3 process, the solutions showed a stimulating effect towards V. fischeri.