His research areas of interest include tobacco marketing and public policy, branding and brand management, sponsorship-linked marketing and social marketing. He has served as an invited consultant for the Attorney General's Office in the state of California, Health Canada, Physicians for a Smoke-Free Canada as well as the World Health Organization, in which he was named as an expert for the elaboration of a template for a protocol on cross-border advertising, promotion and sponsorship (with respect to the Framework Convention on Tobacco Control). Professor Dewhirst has served as an expert for the plaintiff's counsel in tobacco litigation. Additionally, he is an Associate Editor of Tobacco Control.