What We Do

Analysis of body tissues and fluids for the presence of drugs including alcohol in support of medico-legal death investigations and criminal investigations including impaired driving, homicide, and sexual assault.


Responsible for the analysis of body tissues and fluids for the presence of drugs including alcohol. This is important when the presence or absence of drugs is important to a case, such as coroner's death investigations, impaired driving, sexual assault, fire death, and homicide cases. The analytical results, and their associated interpretation, in these cases are communicated through written reports and expert witness testimony at all levels of court in Ontario. Most frequently, expert witness testimony relates to drug and alcohol impaired driving.

Toxicology staff is also responsible for the administration of the breath alcohol testing program in Ontario, which includes providing training to peace officers in the theory and the operation of approved breath alcohol testing instruments used in Ontario.

To obtain a letter of opinion for a Toxicology interpretation, including the calculation of blood alcohol concentrations from hospital, blood, or breath results, submit an LOP request through the Case Submission Portal. Information regarding supporting documentation for these requests is contained within the Case Submission Portal.

Additional Information

Technical Information Sheets

Toxicology Instructional Videos