It's a fast-paced world and, unfortunately, many of our patients seek the assistance of substances to cope and get through their busy, trying days. However, the use and abuse of both illicit and licit substances has the potential to produce systemic adverse reactions and life-threatening medical emergencies during dental treatment. This course will provide attendees with an overview of the most common substances of abuse, along with their potential contraindications to dental therapy and the resulting necessity, if any, for dosage modifications of commonly used dental drugs. Special emphasis will be given to a discussion of patients using marijuana (cannabis) for both medical and recreational purposes.