<![CDATA[Adolescent girls' anemia continues to be a significant public health concern despite ongoing iron supplementation and screening programs. Health education may improve knowledge, attitudes, and preventive practices pertaining to preventing anemia. The purpose of this study was to assess changes in knowledge, attitudes, and preventive practices among adolescent girls following a health education program supported by leaflets and posters. A pre-experimental one-group pretest-posttest study was conducted from May to June 2026 among 100 female participants aged 17-20 years who were active members of Karang Taruna “Tunas Mekar” in Gondangrejo District, Karanganyar Regency, Indonesia. All eligible members were included through total sampling. Participants completed a validated and reliable questionnaire immediately before the intervention and seven days afterward. Paired scores were analyzed using the Wilcoxon signed-rank test, and effect sizes were calculated as r = Z/√N. Following the intervention, median knowledge, attitude, and preventive-practice scores increased from 10 (IQR 8-12) to 13 (IQR 12-14), 28 (IQR 25-31) to 33 (IQR 31-36), and 6 (IQR 5-7) to 8 (IQR 7-9), respectively. There were notable variations between the pre-test and post-test results for knowledge, attitudes, and preventive practices (all p < 0.001), with moderate effect sizes (r = 0.394-0.411). Short-term improvements in knowledge, attitudes, and self-reported preventive practices were observed following the health education program. These findings suggest that leaflet- and poster-assisted health education may be a practical component of community-based anemia prevention programs; however, long-term efficacy must be confirmed by controlled studies with extended follow-up]]>
