What is chemotherapy and why does it cause side effects?

Drugs that kill rapidly dividing cells. Because healthy fast-dividing cells — bone marrow, hair follicles, gut lining — are also affected, side effects include low blood counts, hair loss, nausea, and mouth sores. Newer targeted and immune therapies have different, sometimes milder, profiles.

Side effects vary enormously by regimen. Ask the oncology team specifically which ones apply to his protocol rather than preparing for all of them.

Fever during chemotherapy is a medical emergency — neutropenic sepsis can progress within hours and needs immediate hospital assessment, not a wait-and-see approach.