Medication injury in the gastrointestinal tract (GIT) is a rapidly evolving topic. Increasing endoscopy together with an ageing population, polypharmacy, and a burgeoning drug industry offer heightened opportunities to observe the unintended side effects of therapeutic ingestants. In this review, we emphasise the most commonly encountered medication injuries involving the GIT, as well as emerging agents and mimics. While topics are organised by organ system, the reader should keep in mind that injury patterns are generally not site-specific. As such, awareness of these major morphologic patterns can be translated to multiple tissue sites to more broadly facilitate the diagnostic process.