RESUMO
BACKGROUND: Many educational technologies have been used to promote the health of the population. Thus, the objective was to assess the effect of using an individual educational primer along with the Brief Motivational Interviewing (BMI) for increasing maternal self-efficacy for preventing childhood diarrhoea. METHODS: Randomized clinical trial, conducted in Fortaleza/Ceará-Brazil, composed of 181 mothers and/or guardians of children under five years, who were randomized into three groups: experimental group A (EG A)-who read the primer, experimental group B (EG B)-application of the primer and BMI and the control group (CG). The participants' assessment was based on the Maternal Self-Efficacy Scale for Preventing Childhood Diarrhoea and the diarrhoea Investigation Form at the beginning of the intervention and then 30 and 60 days after the first contact with the participants. RESULTS: There were 60 participants in EG A and CG and 61 in EG B. It was noted a greater incidence of participants with high self-efficacy in EG B after applying the technologies. All groups manifested diarrhoea among children after the interventions, although with a lower number in EG B, one-month post-intervention (P = 0.025). CONCLUSIONS: The combined use of the primer and the BMI contributed significantly over time to increase maternal self-efficacy in preventing childhood diarrhoea and reduce cases of this disease.