The Bureau is responsible for chemical testing for intoxicants (alcohol and other drugs) in drivers in Ireland. Services are provided to An Garda Síochána, the Irish Aviation Authority, the Department of Transport, the Courts, defence and prosecution lawyers, and to the public.

Specimens from across the country are delivered to the Bureau daily for testing. The Bureau also tests and approves Alcohol Interlock Devices, which is of emerging and growing importance in road safety in Ireland as part of the National Road Safety Strategy. The ongoing evaluation and approval of Alcohol Interlock Devices reflect Ireland's commitment to enhancing road safety and reducing instances of impaired driving. As of 2025, five devices have been MBRS approved. In 2025, a total of 6,087 blood and urine specimens were received for alcohol and/or drug testing. This represented a 3% increase on 2024. Also in 2025, 2,539 (2,297, 2024) specimens indicated a positive drug result for at least one of the drugs that can detect. Cannabis and Cocaine are two most frequently detected drugs. Our data shows that there has been a significant increase in the presence of Cocaine up from 43% in 2019 to 58% in 2025. The presence of Cannabis has dropped to 55% in 2025, down from 66% in 2019.