Chemotherapy has been one of the four major cancer treatment modes for several decades; the other three are surgery, radiation, and immunotherapy. This article presents breast cancer as a model for understanding chemotherapy because, given its prevalence in American populations, the home care provider is highly likely to encounter clients with this diagnosis. Detailed explanations of the categories and pharmacodynamics of cytotoxic drugs are beyond the scope of this article. As always, caregivers should study specific drugs when individual clients are taking them. However, because most cancer patients receive a combination of chemotherapeutic agents and many agents are indicated for a variety of primary tumors, similarities exist in the toxicities clients experience and the appropriate management strategies.