In a sample of 382 heavy users mode and extent of drug abuse were inquired. Factor analysis of the data gave three factors named "i.v. applicated illegal drugs", "oral applicated illegal drugs" and "oral applicated medicaments" for short. Results show that attitudes of the drug users towards their drug uses are strongly influenced by the mode of application and the definitions of the drug laws, whereas pharmacological aspects and subjective effects have hardly any demonstrable importance.