Until recently, much of the medical and psychological literature has examined and conceptualized the taking of medication from the viewpoint of adherence to or compliance with recommendations from health professionals. However, some authors have argued that medication taking is mostly determined by patient decision making. In order to investigate the factors and processes influencing the patient's decision to take or not take abortive therapy for migraines, 20 migraineurs (according to International Headache Society criteria) were asked, using a semistandardized interview, what factors influenced their decision to take or not take sumatriptan when they had a migraine. Qualitative analysis revealed a 2-stage decision-making process. First, the patient collects information from interoceptive and environmental cues (symptom monitoring) to predict whether the headache that is beginning will become a migraine. Then, if the patient decides it is a migraine, he or she weighs various factors to decide whether to take sumatriptan. These results are consistent with the current cognitive psychology literature on decision-making processes and could lead to significant improvements in understanding the process by which patients make decisions about taking sumatriptan and, ultimately, could lead to better patient education and more effective headache control. They also open a whole new field in the empirical investigation of medication-taking behavior.