The purpose of this case study was to examine the daily symptom experience of a teenage girl, Abby, undergoing treatment for cancer. Quantitative and qualitative data collection and analysis techniques were used to ascertain patterns in daily experiences of pain, nausea, vomiting, retching, stress, sleep alterations, and anxiety. A time-series analysis focused on change and variability in patterns of symptom data. A key finding was that the predictability evident in Abby's symptom patterns were in direct contrast to her perception that there was no predictability or pattern to her symptoms. Her perceived lack of control over her symptoms generated worry, anxiety, and depression and led Abby to question whether she could continue with the treatment. Abby represented a case of "fighting the treatment," as opposed to "fighting the cancer," and it is the difference between these responses that may explain children's overall ability to tolerate intensive chemotherapy.