Lan capsules, containing the active ingredient lansoprazole, are used to inhibit stomach acid production and treat conditions such as duodenal and gastric ulcers, gastroesophageal reflux disease (GERD), and Zollinger-Ellison syndrome. The product is available in 15 mg and 30 mg strengths and is manufactured by Intas Pharmaceuticals. Usage precautions include potential allergic reactions, risks of prolonged treatment effects, and specific considerations for pregnant patients.