OBJECTIVES: To analyse the opinions and attitudes reported by medical specialists regarding online health information and their interference in the doctor-patient relationship. Methods: A cross-sectional study developed between 2016 and 2017 in Recife-Pernambuco-Brazil, which used a questionnaire in person in a population of 183 specialists from the Instituto de Medicina Integral Prof. Fernando Figueira. The results were analysed through the Statistical Package for the Social Sciences. Obtained approval of the Ethics Committee under the voucher number 121004/2016. Results: In the opinion of 85.2% of physicians, online health information has both positive and negative impacts on the physician-patient relationship. Faced with a questioning patient who claims to have researched information on the internet, 98.9% of the physicians said they would try to explain the reasons for their diagnosis and treatment. 59% already had a patient who modified the treatment recommended after seeing health information on the Internet. 73.8% agreed that online health information has positive effects for the general public, but 89.1% feel that most patients do not know which online health information is reliable. CONCLUSION: The physicians surveyed view online health information in a positive way, but realize that it is necessary to be cautious as to their repercussions on the treatment of patients. There is concern about the accuracy of online health information, and it is incumbent upon the physician and health institutions to instruct patients about the sources of quality and that they are able to understand, as its known the patients have an active voice through the guarantee of the ethical principle of autonomy. KEYWORDS: Internet. Physician-patient relations. Physician’s role. Patient participation.