Objective: To describe consequences of the nonmedical use (NMU) of prescription amphetamines (AMPs). Method: Data from the U.S. National Poison Data System yielded four groups: intravenous NMU ( IV NMU) intentionally injected AMP, Nasal NMU intentionally inhaled AMP but did not inject, Oral NMU intentionally ingested AMP, and controls reported unintentional oral exposure to AMP. Results: The Nasal NMU group was at greater risk of admission to a health care facility. All NMU groups were at greater risk for adverse clinical effects. IV NMU had the greatest number of adverse effects, followed by Nasal and Oral NMU. Nasal NMU had a greater risk for major medical outcomes versus Oral NMU. The IV NMU group was 21.9 times more likely to die from AMP NMU than controls. Oral NMU conferred a significantly greater risk of suicide attempts. Conclusion: Oral and nonoral NMU of AMP are associated with significant risks of morbidity and mortality.