Summary:Dopamine agonists have been used with some success in treating cocaine addiction. However, both cocaine and psychostimulants have been reported to produce neurotoxic effects. We evaluated the effect of the stimulant diethylpropion on cognitive performance in a double‐blind, placebocontrolled trial. Forty‐six abstinent crack‐cocaine users received either placebo, 25‐mg, 50‐mg, or 75‐mg doses of diethylpropion. Patients were tested at baseline and again after 9‐14 days of medication. There were no differences between placebo and medication groups on any test, indicating that, within the time frame studied, diethylpropion does not produce neurotoxic effects that can be detected with standardized neuropsychological tests.