Some medications, especially aspirin, anticoagulants (blood thinners), non-steroidal anti-inflammatory drugs (NSAIDs), and certain antibiotics, can cause irritation of the mucosa of the stomach, duodenum, and esophagus. The main problems caused by this irritation are ulcer formation, associated pain, burning, and bleeding. Patients with a history of gastrointestinal bleeding, gastritis, ulcers, or reflux should exercise greater caution when using such medications. Based on the patient's history and assessment, the physician may opt for medications with fewer gastrointestinal side effects or may plan concomitant gastric protective treatment.