Class of 2011 Abstract / OBJECTIVES: Accidental ingestions of medications in children under five years old are an increasing problem faced by parents and caregivers. This study will determine which medications are most commonly ingested and which cause more harmful side effects. METHODS: A descriptive, retrospective study was performed by obtaining data from electronic patient charts from the Arizona Poison and Drug Information Center (APDIC). Subjects were selected if they were younger than five years old and had ingested a medication during 2009. Age and gender were analyzed by calculating percentages and means and comparing them using an independent t-test. Adverse effects of medications were compared using a Chi Square test. RESULTS: A total of 4,373 cases met inclusion criteria for analysis, including 2,019 females and 2,354 males. The average age of patients was 2.2 years. Of 3,275 cases (74.4%) involving OTC medications, 119 patients (3.6%) developed minor effects and 20 patients (0.6%) developed moderate effects. Of 1,129 children (25.6%) ingesting prescription medications, 78 patients (6.9%) developed minor effects, 35 patients (3.1%) developed moderate effects and 1 patient (0.1%) developed a major effect (p=0.003). CONCLUSION: Males were more likely to have unintentional ingestions than females. The incidence of OTC ingestions was higher than prescription ingestions. Toddlers tended to have more ingestions than infants or older children. Unintentional prescription medication ingestions resulted in significantly more adverse effects than unintentional OTC ingestions.