What is the best medication for an ulcer in the stomach?

If caused by bacteria: Antibiotics and acid-reducing drugs.
 
If caused by acid: Acid-reducing drugs like proton pump inhibitors (PPIs) or H2 blockers. If you are looking for genuine stomach ulcer cure then must try ranitidine 150 mg

Antibiotics: These kill the bacteria (H. pylori) that often causes ulcers.

Acid-reducing drugs:
Proton pump inhibitors (PPIs): Strongly reduce acid production.

H2 blockers: Lessen acid production.
Antacids: Neutralize stomach acid, providing quick relief.
Bismuth subsalicylate (Pepto-Bismol): Protects the stomach lining and kills bacteria.

Important: Always consult a doctor for the right treatment plan as ulcers can have different causes and severities.