Herceptin (Trastuzumab) is a targeted cancer treatment used to treat HER2-positive breast cancer and certain types of stomach cancer. It works by blocking the HER2 protein, which promotes the growth of cancer cells. Herceptin is often used in combination with chemotherapy to improve treatment outcomes. It is administered intravenously and requires supervision by a healthcare professional. With a valid prescription, Herceptin is available from specialized pharmacies for cancer treatment.