Hi, dear I have gone through your question. I can understand your concern. She has small cell cancer of lung. Fever is common while patient is on chemotherapy. Chemotherapy kills the cancer cells but along with that it also kill normal body cell. It causes suppression of normal bone marrow cells. It leads to frequent infection and fever. So higher antibiotics and antipyretic drugs are needed with chemotherapy. Consult your doctor and take treatment accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using health care magic. Wish you a very good health.