Data on incidence, medical spending, and payment sources for poisoning were taken from the 1987 National Medical Expenditure Survey, 1991 US Vital Statistics, the 1992 National Hospital Discharge Survey, and 1992 poison control center surveillance data. Benefits, measured as percentage reductions in medical spending attributable to use of poison control centers, were calculated from analyses of published and unpublished studies of jurisdictions in which services became unavailable. Medical spending (payments) for poisoning treatment totaled $3 billion in 1992. Spending averaged $925 per case. Poison control center services were available for 86% of poisonings As used, they reduced the number of patients who were medically treated but not hospitalized for poisoning by an estimated 350,000 (24%) and the number of hospitalizations by 40,000 (12%) in 1992. The average public call to a poison control center for aid prevented $175 in other medical spending. Poison control centers offer a large return on investment. Despite their proven benefits, many poison control centers are unstably funded and financially strapped, in part because the federal government pays far less than its fair share of center costs.