After graduating from the veterinary program at the University of Bristol, U.K., with honors, in 1991 Dr. Lascelles completed a PhD in aspects of pre-emptive/perioperative analgesia at the University of Bristol. After an internship there, he completed his surgical residency at the University of Cambridge, U.K. He moved to Colorado for the Fellowship in Oncological Surgery at Colorado State University, then a period of post-doctoral research in feline pain and analgesia at the University of Florida, and is currently Professor in Small Animal Surgery and Pain Management at North Carolina State University. He is board-certified in small animal surgery by the Royal College of Veterinary Surgeons, the European College of Veterinary Surgeons, and the American College of Veterinary Surgeons.

He is director of the Comparative Pain Research and Education Centre (CPREC). His research program (Translational Research in Pain [TRiP]) is dedicated to answering critical questions about pain control and pain mechanisms through high quality, innovative research. His career has been focused on developing algometry methods (methods to measure pain) in spontaneous disease animal models (pets with naturally occurring disease), and probing tissues from well-phenotyped animals with spontaneous disease to understand the neurobiology, with a strong translational focus. The aim of his research is to improve pain control in companion animals, and facilitate analgesic development in human medicine. He has authored over 180 peer reviewed research papers and reviews and 190 research abstracts, as well as over 30 book chapters.