The aim of this study is to investigate the concentrations of ethyl glucuronide (EtG) in oral fluid and both EtG and ethyl sulfate (EtS) in blood and urine following intense use of mouthwash and ingestion of nonalcoholic wine, which are proven to contain 3 mg/L EtG, 1.5 mg/L EtS, and 0.2 g/L ethanol. Twelve subjects participated in a controlled experiment. All subjects ingesting nonalcoholic wine showed urine samples negative for EtG but positive for EtS (Cmax 2.15 mg/L). All four subjects using mouthwash were negative for EtG and EtS in urine. All samples of oral fluid were negative for EtG and all samples of blood were negative for EtG and EtS. This study showed that ingestion of EtG and EtS as components of nonalcoholic wine lead to detection of urine EtS only, suggesting superior bioavailability of orally ingested EtS compared to EtG. This possibility of false-positive EtS results in urine after ingestion of nonalcoholic wine is important to remember when using EtG and EtS as relapse markers for alcohol. Finally, the study showed that a positive EtG or EtS result after accidental alcohol exposure is unlikely in blood and oral fluid.