Patients use various sources to obtain information on pharmaceutical drugs they take. Mobile health care applications (apps) providing drug information to users are increasingly made available and of increasing importance for the health care domain. However, apps usually only offer functionality that medical professionals or developers consider useful for patients, although their expectations are not likely to meet patient expectations. In our mixed methods study, we identify 33 features patients expect in apps for drug information provision with interviews and empirically assess their perceived importance in an online survey. Results indicate that patients desire personalization features for provided information but not for the app interface. This work contributes to research and practice by identifying and empirically ranking drug information provision features patients find important. We furthermore establish a foundation for future research on effective mobile drug information provision and provide insights for practice on development of patient-centered mobile health apps.