Method: Individuals searching for information about alcohol or drugs online who scored over 0 on the Drug Use Disorders Identiﬁcation Test (DUDIT) and were 15 years or older were recruited for this trial and randomized into one group receiving Internet-based screening and brief intervention via eScreen.se(n = 101) or one assessment-only control group (n = 101). Both groups were screened at baseline and followed up at 3 and 6 months. The primary outcome measure was the DUDIT-C score and secondary outcome measures were DUDIT, AUDIT-C (Alcohol Use Disorders Identiﬁcation Test-C) and AUDIT scores.Additional outcomes included the proportion of drug abstainers and those who made a clinically signiﬁcant change in their alcohol and drug use. Four statistical models of analysis were used to conservatively assess results.