Purpose: This study is part of a larger project, which aims to develop medicine education materials for teachers. The aim of the present study was to discover children's interests in medicines and teachers' opinions on what should be taught about medicines to children of different ages. Furthermore, teachers' opinions were assessed about the importance of medicine education as a part of school health education. The aim of the recommendations, based on our research and the materials developed during this process, is to clarify what proper use of medicines can mean, and in this way help teachers fulfil the requirements of the new Finnish health education curriculum. Design/methodology/approach: Twelve focus group discussions were conducted among a convenience sample of first-graders (7-8 years, n = 23), fourth-graders (10-11 years, n = 24) and seventh-graders (13-14 years, n = 19). A national representative survey was conducted to gather data from the teachers (n = 284, response rate 71 percent). Findings: Children's interests and teachers' opinions on what could be taught about medicines to children of different ages were quite similar. However, fourth-graders were interested in many topics which teachers considered suitable for older children, for example, how medicines work, how to avoid adverse reactions, and abuse of medicines. The vast majority of the teachers (93 percent) considered teaching about the proper use of medicines so important that it should be included in the national curriculum of health education. Of the children, fourth-graders were the most interested in medicines. Originality/value: This is one of the first studies, which combines the opinions of children and teachers, on what to teach children of different ages about the proper use of medicines. During the study, evidence-based recommendations on what to teach children about medicines and teaching materials were created. (Contains 4 tables and 1 figure.)