SummaryTwenty‐two amphetamine‐dependent subjects, all imprisoned drug abusers, with a history of at least one year of intravenous abuse of central stimulants, were used for evaluation of the subjective effects of the two weight‐reducing drugs fenfluramine and AN 448. During four different days, each subject received a single dose of the following drugs in a double‐blind study with cross‐over design: AN 448 2 mg, fenfluramine 80 mg, amphetamine 50 mg and placebo. A self‐rating scale for the factor “CS effect” was used before drug intake, and 1, 3 and 6 hours thereafter. A question of “similarity to amphetamine” was posed at 6 hours after drug intake. Some subjects experienced a low degree of amphetamine‐like effect from AN 448, whereas no such effect was found for fenfluramine. With regard to the factor “CS effect”, AN 448 and fenfluramine di