Background/Aims: Berberine ursodeoxycholate (HTD1801) has been shown to significantly reduce liver fat content (LFC) in an 18-week, placebo-controlled Phase 2 study in patients with metabolic dysfunction-associated steatohepatitis (MASH) and type 2 diabetes mellitus. The purpose of this assessment was to establish proof of concept in liver histologic improvement with HTD1801 treatment based on preclinical and clinical evidence.Methods: The efficacy of HTD1801 was evaluated in a preclinical MASH/dyslipidemia model (golden hamsters fed a high fat diet, eight/group) after six weeks of daily treatment. Additionally, in a secondary analysis of a Phase 2 clinical study, 100 patients with presumed MASH were evaluated by multiple noninvasive markers associated with MASH resolution and/or fibrosis improvement. These include magnetic resonance imaging proton density fat fraction (MRIPDFF; ≥30% LFC reduction), iron-corrected T1 (≥80 ms reduction), alanine aminotransferase (≥17 U/L reduction), weight loss (≥5% reduction), Fibrosis-4 index (shift to <1.3), and MASH resolution index (achieving ≥–0.67).Results: Preclinical findings in the MASH/dyslipidemia hamster model showed that HTD1801 significantly improved histologic fibrosis and the Nonalcoholic Fatty Liver Disease Activity Score to such a degree that improvements approximated the appearance of the normal controls. In the clinical study, 52% of HTD1801-treated patients achieved MRI response criteria compared to 24% of placebo (<i>p<0.05). Dose-dependent improvements were observed across biomarkers, with more HTD1801-treated patients achieving response criteria associated with improvements in the histologic features of MASH.Conclusions: These findings suggest that HTD1801 has strong potential to produce histological improvements in patients with MASH.