Chemotherapy drugs are medications that are used to treat cancer. They work by killing or stopping the growth of cancer cells, either by damaging their DNA or interfering with their ability to grow and divide. Chemotherapy can be given in different ways, such as through injection into a vein or muscle, orally, or directly into the area where the cancer is located. The specific drugs used will depend on the type of cancer being treated, its location, and how advanced it is. Common side effects of chemotherapy include fatigue, nausea, vomiting, hair loss, and an increased risk of infection due to a weakened immune system. However, modern chemotherapy drugs have come a long way in terms of targeting cancer cells while minimizing damage to healthy cells, resulting in fewer side effects for patients.