Patients use various sources to obtain information on pharmaceutical drugs. Mobile health care applications (apps) providing drug information to users are increasingly made available and of rising importance for the health care domain. However, apps usually offer functionality that only medical professionals or vendors consider useful for patients, although their considerations are not likely to meet patient expectations. In our exploratory 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.