In vivo metabolism of (+)-N-(n-propyl)amphetamine (NPA) in man (2 subjects) produced, among other products, two conjugated phenolic metabolites which are identified as 1-(4-hydroxyphenyl)-2-(n-propylamino)propane and 1-(4-hydroxy-3-methoxyphenyl)-2-n-propylamino)propane. In a 24 hr urine sample (pH uncontrolled), 13.4% of the NPA administered was excreted as the former, and 3.5% as the latter metabolite.