BACKGROUND: Parent medication errors are exceedingly common, with one child experiencing an outpatient medication error every 8 minutes. In a previous randomized controlled trial where the intervention was carried out under ideal conditions, we examined the efficacy of a pictographic, health literacy-informed medication instruction sheet-based intervention (HELPix) in reducing parent dosing errors. While our intervention was efficacious in reducing errors, reproducing these results in a real world setting, is necessary to examine the true effectiveness of HELPix. OBJECTIVES: 1) To examine the impact of HELPix implementation on parent medication dosing errors. 2) To assess the effect of HELPix implementation on provider use of medication counseling strategies. DESIGN/METHODS: A pre-implementation/post-implementation study design was used in 2 pediatric Emergency Departments (EDs) in New York City, one with planned implementation of the HELPix intervention (HELPix site) and the other a control site within the same hospital network. Subject inclusion criteria included: 1) English or Spanish-speaking parent, 2) child <9 years old, child prescribed a short course (≤14 days) daily liquid medicine, and 3) parent present with the child in the emergency department and received medication counseling. Parents were recruited over the phone; those who enrolled completed a phone interview along with a follow-up in-person assessment (median time to follow-up=15 days). ED providers (residents, fellows, attendings) were also recruited. The HELPix intervention consists of: 1) provider provision of patient- and medicine-specific pictographic instruction sheets, 2) provider use of pictures/drawings as part of counseling to reinforce dosing information, 3) provider demonstration of the dose using an oral syringe, 3) teachback of dose information, 4) parent showback of the dose they plan to give, and 5) provider provision of an oral syringe. At the HELPix site, ED providers were trained in the use of HELPix counseling strategies as well as how to use the electronic medical record (EMR) system to generate the instruction sheets while ordering a prescription. Outcomes assessed were: 1) provider provision of HELPix instruction sheets via web tracking, 2) dosing errors ≥ 20% deviation from prescribed dose, assessed from observation at follow-up visit, 3) provider counseling practices (i.e. use of pictures/drawings, demonstration, teachback, showback, provision of dosing tool) obtained by parent report. RESULTS: A total of 1493 parents were assessed by telephone for eligibility in the pre-/post-implementation phases. 561 parent-child dyads were recruited by phone (284 at HELPix site; 277 at control site). A total of 92% were mothers, 52% were Spanish speakers, 78% were Latino, 16% were Black, and 85% were of low socioeconomic status. Web tracking at the HELPix intervention site indicated that for 58% of the enrolled families in the post-implementation period, providers generated HELPix medication instruction sheets. Compared to the pre-implementation period at the intervention site, parent dosing errors rates were significantly reduced during the post-implementation period (37% versus 16%; AOR=0.3, p<0.001); with an overall Relative Risk Reduction (RRR)=57%, with greatest reductions in errors among those that received HELPix sheets (12% error rate, RRR=68%). Providers at the HELPix implementation site were significantly more likely to use recommended provider counseling strategies post-implementation compared to pre-implementation (pictures/drawings: 37% versus 1%; dosing demonstration: 59% versus 33%; teachback: 24% versus 8%; showback: 33% vs. 13%, and provision of oral syringe 79% versus 25%; p<0.0001 for all strategies). In the non-intervention site, there were no differences in parent dosing error rates, or in provider use of counseling strategies between the pre- and post-implementation periods. CONCLUSION: Implementation of the HELPix intervention resulted in increased provider use of recommended counseling strategies as well as decreased parent medication dosing errors in an urban public hospital setting serving low socioeconomic status families. Use of HELPix supports high quality provider medication counseling and appears to be feasible to incorporate as part of routine Emergency Department discharge practices.