Abstract Background Molecular Adsorbent Recirculating System (MARS®) is a non-biological artificial liver device. The benefit risk ratio between uncertain clinical effects and potential adverse events remains difficult to assess. We sought to describe adverse events related to MARS® therapy as well as biological and clinical effects. Methods All intensive care unit (ICU) admissions to whom MARS® therapy was prescribed from March 2005 to August 2021 were consecutively and prospectively included. The main endpoint was the incidence of adverse events related to MARS® therapy. Secondary endpoints were the biological and clinical effects of MARS® therapy. Results We reported 180 admissions treated with MARS® therapy. Among the 180 admissions, 56 (31.1%) were for acute-on-chronic liver failure, 32 (17.8%) for acute liver failure, 28 (15.5%) for post-surgery liver failure, 52 (28.9%) for pruritus and 12 (6.7%) for drug intoxication. At least one adverse event occurred in 95 (52.8%) admissions. Thrombocytopenia was the most frequent adverse event which was recorded in 55 admissions (30.6%). Overall, platelets count was 131 (± 95) × 109/L before and 106 (± 72) × 109/L after MARS® therapy (p