Chemotherapy works by killing cells that are rapidly dividing, such as cancer cells.
As well as killing cancer cells, chemotherapy also kills normal cells that are rapidly dividing. However, unlike cancer cells, normal cells can repair the damage and can recover.
The main areas of the body that are affected by chemotherapy are the mouth, stomach and bowel (gut), skin, hair and bone marrow. Damage to these normal cells causes the side effects of chemotherapy.