AbstractBACKGROUNDLiquid hazardous medical wastes (LHMW) originating from health‐care laboratory services present a global environmental hazard as most sustainable wastewater treatment technologies fail to address this particularly demanding issue. In this study, heterogeneous and homogeneous photocatalytic oxidation of simulated and real LHMW has been performed at bench scale, investigating their potential to decompose and detoxify such effluents.RESULTSA simulated LHMW of 0.4 g L−1 DOC0 was photocatalytically treated in the presence of TiO2 P25. The addition of H2O2 was necessary to achieve mineralization, while the optimal concentration of P25 for this purpose was 1.0 g L−1. In the case of photo‐Fenton, under optimal conditions (0.056 g L−1 Fe3+, 3 g L−1 H2O2, UV‐A, pH 3.0) complete mineralization was accomplished in 600 min of illumination, while phytotoxicity was eliminated or significantly reduced, depending on the employed plant species. Photocatalytic processing of real LHMW (400 mg L−1 DOC0, 1.0 g L−1 TiO2 P25, 2.5 g L−1 H2O2, UV‐A or 0.056 g L−1 Fe3+, 3.0 g L−1 H2O2, UV‐A, pH 3.0) led to mineralization rates ranging from 55.5% to 95% after 900 min. Variations in ecotoxicity followed the mineralization profile for most samples. Partial mineralization failed to reduce toxicity in most samples, suggesting the generation of toxic intermediates; however, when mineralization exceeded 85%, ecotoxicity was in most cases efficiently removed.CONCLUSIONLaboratory LHMW are highly recalcitrant both in terms of mineralization and detoxification. However, photocatalytic oxidation may serve as an efficient processing tool, providing alternative or complementary solutions to this highly challenging issue. © 2021 Society of Chemical Industry (SCI).