The goal of this clinical trial is to learn if including bismuth in the treatment helps heal stomach and duodenal ulcers caused by Helicobacter pylori (H. pylori) in children. The main questions it aims to answer are: * Does a treatment plan with bismuth work better than a plan without bismuth to clear the infection? * Is the bismuth plan more cost-effective while still safe and effective? Researchers will compare two treatment groups to see which works better. Participants will: * Take one of the two assigned treatment plans (with or without bismuth) for the standard treatment duration * Visit the clinic for checkups and tests to confirm infection clearance and monitor side effects * Keep a diary of symptoms, medication use, and any side effects