BackgroundInappropriate dispensing of antibiotics for acute respiratory illness (ARI) is common among drug sellers in Bangladesh. In this study, we evaluated the impact of an educational intervention to promote guidelines for better ARI management among drug sellers.MethodsFrom June 2012 to December 2013, we conducted baseline and post-intervention surveys on dispensing practices in 100 pharmacies within Dhaka city. In these surveys, drug sellers participated in 6 standardized role-playing scenarios led by study staffs acting as caregivers of ARI patients and drug sellers were blinded to these surveys. After the baseline survey, we developed ARI guidelines and facilitated a one-day educational intervention about ARI management for drug sellers. Our guidelines only recommended antibiotics for children with complicated ARI. Finally, we conducted the six month post-intervention survey using the same scenarios to record changes in drug dispensing practices.ResultsOnly 2/3 of participating pharmacies were licensed and few (11%) of drug sellers had pharmacy training. All the drug sellers were male, had a median age of 34 years (IQR 28–41). For children, dispensing of antibiotics for uncomplicated ARI decreased (30% baseline vs. 21% post-intervention; p = 0.04), but drug sellers were equally likely to dispense antibiotics for complicated ARI (15% baseline vs. 17% post-intervention; p = 0.6) and referrals to physicians for complicated ARIs decreased (70% baseline vs. 58% post-intervention; p = 0.03). For adults, antibiotic dispensing remained similar for uncomplicated ARI (48% baseline vs. 40% post-intervention; p = 0.1) but increased among those with complicated ARI (44% baseline vs. 78% post-intervention; p < 0.001). Although our evidence-based guidelines recommended against prescribing antihistamines for children, drug sellers continued to sell similar amounts for uncomplicated ARI (33% baseline vs. 32% post-intervention; p = 0.9).ConclusionsDespite the intervention, drug sellers continued to frequently dispense antibiotics for ARI, except for children with uncomplicated ARI. Pairing educational interventions among drug sellers with raising awareness about proper antibiotic use among general population should be further explored. In addition, annual licensing and an reaccreditation system with comprehensive monitoring should be enforced, using penalties for non-compliant pharmacies as possible incentives for appropriate dispensing practices.Electronic supplementary materialThe online version of this article (10.1186/s12913-018-3486-y) contains supplementary material, which is available to authorized users.