To inform Medicaid medication management and public health policymaking, the authors analyzed the major predictive factors influencing program-approved therapeutic use or poisoning E-coded encounters leading to emergency department visits and hospital admission for the totality of Michigan Medicaid beneficiaries during a 12-month 2010-2011 period. The analytic cohort was composed of 26,134 approved E-code encounters submitted for 19,865 discrete Michigan Medicaid beneficiaries.More than 1% of all beneficiaries experienced at least one adverse medication/agent-related E-code encounter during the period. More such encounters and costlier approved encounters were recorded female subjects, African Americans, dually eligible adults, urban elderly, those with fee-for-service Medicaid coverage, and those residing in urban-density counties.Especially notably for patient safety policymakers, more than 9% of total E-coded encounters for children and adults were primarily attributed by providers to likely preventable poisoning causes such as exposure to household cleaning agents/gases, cosmetic products, illicit drug/alcohol, or secondary tobacco smoke. Encounter costs for the total sample totaled $37 million but ranged considerably up to more than a quarter million dollars.In view of the future expanding Medicaid-covered beneficiary cohorts, the authors propose several key patient safety/public health policy implications for researchers and policymakers striving to serve lower-income health care consumer groups.