photo by Rhoda Baer, NCI

Chemotherapy involves the application of drugs (chemicals) to treat cancer. This treatment has been around since at least 1943. Traditionally, chemotherapeutic drugs fall into certain classes according to the activity they perform within the cell. All living cells—both healthy and cancerous—go through a complicated process of division known as mitosis. Chemotherapy drugs take advantage of this five-stage process by inhibiting the cell's ability to complete one or more of the stages1. Chemotherapy drugs with these functions are known as cytostatic drugs (cyto = cell, static = interference).

What it's effective for and why

Chemotherapy is most effective against aggressive cancers because the cells in high-grade cancers divide frequently, giving the drugs more opportunities to inhibit the process. On the other end, chemotherapy is not as effective against indolent (or slow-growing) cancers.

Although widely associated with intravenous (IV) administration, chemotherapy can also be given in the form of an injection, an oral pill or liquid, and even as a topical cream2.

Side effects: Overview

The primary drawback to chemotherapy is that the drugs are indiscriminate; they don't just kill cancer cells, they also kill healthy cells. The death of these healthy cells is what generally causes the side effects associated with this treatment type, such as hair loss, fatigue, and problems with digestion. The areas of the body most affected by chemotherapy are the ones which feature fast-dividing cells, such as the hair follicles, the mucous membranes in the mouth, the cells lining the entire digestive system, and those in the reproductive systems3.


  1. American Cancer Society: Chemotherapy principles
  2. National Cancer Institute: Understanding Chemotherapy
  3. OncoLink: Chemotherapy Primer

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