What is the difference between chemotherapy and immunotherapy?

Chemotherapy and immunotherapy are both types of cancer treatment, but according to the National Cancer Institute (NCI) they work in fundamentally different ways. Chemotherapy is a type of cancer treatment that uses drugs to kill cancer cells; NCI explains it works by killing or stopping the growth of cancer and other fast-growing cells. Because cancer cells grow and divide quickly, chemotherapy targets them, though it can also affect healthy fast-dividing cells, such as those in the mouth, intestines, and hair follicles. Immunotherapy, by contrast, is a type of cancer treatment that helps your immune system fight cancer. NCI describes it as a form of biological therapy that helps the immune system act better against cancer. In short, chemotherapy acts directly on cancer cells using drugs, while immunotherapy works by helping the body's own immune system. This is general information, not personal medical advice; discuss treatment options with your care team.

Last updated: 2026-07-12

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