The side-effects of chemotherapy depend mainly on the specific drugs and the doses the patient receives. As with other types of treatment, side-effects may vary from person to person. Anticancer drugs generally affect cells that divide rapidly. In addition to cancer cells, these include blood cells which fight infection, help the blood to clot, and carry oxygen to all parts of the body. When blood cells are affected, the patient is more likely to get infections, may bruise or bleed easily, and may feel unusually weak and tired.

Cells in hair roots also divide rapidly; therefore, chemotherapy may lead to hair loss. Hair loss is a major concern for many patients. Some anticancer drugs only cause the hair to thin out, while others may result in the loss of all body hair. People may cope with hair loss better if they decide how to handle hair loss before starting treatment.

Cells that line the digestive tract also divide rapidly, and are often damaged by chemotherapy. As a result, side-effects may include poor appetite, nausea and vomiting, and/or mouth and lip sores.

Most side-effects go away gradually during the recovery periods between treatments or after treatment is over. Sometimes, however, chemotherapy results in a permanent loss of fertility.