What does "chemotherapy" mean and how does it work?

Chemotherapy means treatment with chemical agents, from chemo meaning chemical and therapy meaning treatment. In oncology, chemotherapy uses cytotoxic drugs that kill rapidly dividing cells by interfering with cell division, DNA replication, or other growth processes. Because chemotherapy targets all rapidly dividing cells, not just cancer cells, it also affects healthy tissues like bone marrow, hair follicles, and the gastrointestinal lining, causing side effects such as myelosuppression, alopecia meaning hair loss, nausea, and mucositis.