All teachers filled in the first questionnaire and send it back to the investigator in 1 week. 3 copies of the same educational poster were given to the intervention schools, these schools were requested to display them in 1. the medical room 2. staff common room and 3 anywhere that information was usually placed for the teachers. No poster was given to the control group. After 2 weeks, the posters were removed by the teacher in charge. The same questionnaire was filled in by all the teachers in both groups and sent back in 1 week. The data were processed to show whether the poster was effective to improve the knowledge of the teachers. The study was complied with Declaration of Helsinki and ICH GCP guidelines