Chemotherapy, or chemical therapy, is one form of treatment that involves giving patients anti-cancer drugs. Most of these drugs are known as cytotoxic drugs, which literally means cell (cyto) killing (toxic).
The body is made up of cells and these cells go through cycles of resting, growing and dividing. Different types of cells spend different amounts of time doing these tasks. Cells that grow and divide quickly are more susceptible to chemotherapy. It is during the process of growing and dividing that cytotoxic drugs get into cells and change their make-up so they cannot multiply. As chemotherapy affects cells that divide quickly, it can affect healthy cells too.
Different drugs act at different times of the cycle – some in the growing phase and others in the dividing phase – so for this reason a combination of two or more drugs is often given.