['Fatty liver disease (FLD), of either alcoholic (AFLD) or non-alcoholic (NAFLD) aetiologies, is characterised histologically by features that are lobulocentric that typically affect zone 3, in contrast with portal-based inflammation characteristics of other forms of chronic liver disease.', 'The authors aimed to determine the prevalence and significance of portal inflammation in a cohort of adults diagnosed as having AFLD and NAFLD.', 'From a histology database, the authors identified 160 patients with biopsy proven AFLD and 214 with NAFLD diagnosed between 1991 and 2001. All liver biopsies were reviewed by one pathologist to evaluate various histological features.', 'More than a mild degree of portal inflammation was found in 47% of AFLD compared with 30% in NAFLD subgroup. A higher degree of portal inflammation in AFLD was associated with a higher mean corpuscular volume, gamma glutamyl transferase (GGT) and alkaline phosphatase, and a lower platelet count and albumin, whereas in NAFLD this was associated with age, presence of diabetes, hypertension, body mass index (BMI), higher fasting blood glucose, cholesterol, alanine transaminase, GGT and ferritin. On regression analysis, portal inflammation was associated with the severity of steatosis (p=0.005), presence of ballooning (p=0.030) in NAFLD and severity of fibrosis in both AFLD and NAFLD (p<0.001).'] Is portal inflammation associated with advanced histological changes in alcoholic and non-alcoholic fatty liver disease?