The thiazolidinedione, pioglitazone, is safe and effective for the long-term treatment of patients with prediabetes or type 2 diabetes mellitus (T2DM) who also have nonalcoholic steatohepatitis (NASH), according to new data. In this single-centre, randomized controlled trial, 101 patients with prediabetes or T2DM and NASH received either pioglitazone (45 mg per day) or placebo. Of patients who received the drug, 58% had improved nonalcoholic fatty liver disease scores and 51% had resolution of NASH. Fibrosis scores, hepatic triglyceride content and insulin sensitivity also improved compared with patients given placebo, with no differences in adverse effects seen. However, patients on pioglitazone gained 2.5 kg more weight than those on placebo.