Gemcitabine is a chemotherapy medication used primarily to treat various types of cancer, including pancreatic cancer, lung cancer, and breast cancer. It works by interfering with the cancer cell's ability to grow and divide, ultimately leading to cell death. Gemcitabine is often administered through an intravenous (IV) infusion. This drug is typically given in cycles, allowing the body time to recover between treatments. Common side effects may include nausea, fatigue, and an increased risk of infection due to its impact on the immune system. Regular monitoring by healthcare professionals is essential during treatment.