This study uses literature on the sociology of professions and explores the impact of Internet use on the degree to which patients believe doctors are the sole source of expert medical knowledge. A survey of 406 respondents was conducted to assess this question. Findings lend some support to the idea that the spread of Internet-based professional knowledge erodes the ability of professionals to control their knowledge. Specifically, findings suggest that increased access and use of online health information is related to the belief that doctors may be bypassed in the pursuit of medical information and diagnoses. Indirectly, age was found to be a significant factor, in that the younger the individual, the greater the use of online health information. This finding suggests that Internet use will likely continue to provide challenges to physician authority.