Chemotherapy, also known as chemo, is the treatment of cancer with one or more drugs. Chemotherapy may be used to try to cure a pet of cancer, prolong his or her life, or simply make his or her symptoms less severe.

Chemotherapy may be used in conjunction with other treatment modes, such as surgery and/or radiation therapy.

Chemotherapy drugs work by killing cancer cells (cells that divide rapidly), and as such may also harm cells that are supposed to divide rapidly -- cells of bone marrow, the digestive tract, and hair follicles.