The Real-world Gastritis Initiative (RE.GA.IN.) aims to update the state of the art on gastric inflammatory diseases and provide evidence-based guidance for clinical practice. The initiative, involving scholars from five continents, culminated in a consensus process held in Venice in November 2022 after over 8 months of global scientific deliberations. The consensus process focused on key topics such as epidemiology, *Helicobacter pylori* as the dominant aetiology, gastric autoimmunity, gastric microbiota, endoscopic diagnostics, and histological staging. The ultimate goal is to improve the clinical management of patients with gastritis. The paper reports the conclusions of the RE.GA.IN. consensus, which includes detailed statements on definitions, classification, aetiology, biology, inflammation-driven gastric carcinogenesis, and the clinical priority of histologically reporting gastritis in terms of staging. The consensus emphasizes the importance of accurate diagnosis and management of gastritis to prevent unnecessary interventions and improve patient outcomes.The Real-world Gastritis Initiative (RE.GA.IN.) aims to update the state of the art on gastric inflammatory diseases and provide evidence-based guidance for clinical practice. The initiative, involving scholars from five continents, culminated in a consensus process held in Venice in November 2022 after over 8 months of global scientific deliberations. The consensus process focused on key topics such as epidemiology, *Helicobacter pylori* as the dominant aetiology, gastric autoimmunity, gastric microbiota, endoscopic diagnostics, and histological staging. The ultimate goal is to improve the clinical management of patients with gastritis. The paper reports the conclusions of the RE.GA.IN. consensus, which includes detailed statements on definitions, classification, aetiology, biology, inflammation-driven gastric carcinogenesis, and the clinical priority of histologically reporting gastritis in terms of staging. The consensus emphasizes the importance of accurate diagnosis and management of gastritis to prevent unnecessary interventions and improve patient outcomes.