Acute Gastritis Typically Does Not Cause Diarrhea; Diarrhea Usually Indicates Intestinal Involvement

Acute gastritis is inflammation of the gastric mucosa. Its hallmark symptoms are epigastric pain, nausea, vomiting, early satiety, and sometimes bleeding (hematemesis, melena).

Diarrhea originates from the small or large intestine (increased secretion, decreased absorption, increased motility, exudation). Gastritis alone does not directly cause diarrhea.

When Diarrhea Coexists with Gastritis

• Gastroenteritis: Viral/bacterial infection involving both stomach and intestines (e.g., norovirus, Salmonella).
• H. pylori gastritis + concurrent enteric infection.
• NSAID gastropathy + NSAID enteropathy.
• Systemic illness: Sepsis, thyroid storm, diabetic ketoacidosis.
• Medication side effect: Antibiotics (C. diff), metformin, PPIs (rare).

Isolated acute gastritis → treat with PPI/H2 blocker, sucralfate, dietary modification, H. pylori eradication if positive. Diarrhea warrants separate evaluation (stool studies, hydration, etiology-specific therapy).