<p>The degradation of rosuvastatin (RS), a commonly used blood cholesterol-lowering medicine, was investigated by direct photolysis, UV/hydrogen peroxide and photo-Fenton techniques. In direct photolysis (UV-C, 254&#xa0;nm), the removal of RS (20 mg L^− 1) was calculated to be 71.50, 63.50 and 68.00%, at pH 3, 6 and 11, respectively, after 20&#xa0;min of irradiation. When UV was absorbed by H₂O₂ (0.2 mM) it results in the formation of ^•OH, which increase the degradation efficiecny of RS to 97.7, 86.1% and 82.2% at pH 3, 6 and 11, respectively, only after 20&#xa0;min of treatment. When Fe²⁺ (0.1 mg L^− 1) was added to UV/H₂O₂, 100.0% removal of RS was obtained at 20&#xa0;min of treatment at pH 3. Inorganic ions inhibited the removal efficacy of RS in both UV/H₂O₂ and UV/H₂O₂/Fe²⁺ processes. Furthermore, the TOC removal for UV/hydrogen peroxide and photo-Fenton techniques were found to be 65 and 79%, respectively. Similarly, the total cost for UV/H₂O₂ and UV/H₂O₂/Fe²⁺ processes for one order removal (90% removal) of RS was calculated to be 5.81 × 10^− 2 and 13.0678 $ m^− 3. In addition, density functional theory (DFT) calculations was conducted to determine the reactive sites of various atoms of RS for radical attack. Moreover, three degradation products (DPs) were detected by GC-MS. The aquatic toxicity of these DPs was found to be higher than that of the parent RS. Interestingly, all of the DPs and RS were removed at prolong treatment. In summary, the present work shows that UV/hydrogen peroxide and photo-Fenton techniques can be effectively applied to remove pharmaceuticals and similar organic contaminants from aquatic environments.</p> Graphical abstract <p></p>