GPs are developing sophisticated ways to protect themselves against patients armed with internet printouts.
The first UK study of how GPs respond to printout-wielding patients shows they feel anxious and threatened.
But GPs pull themselves together and use cognitive and behavioural techniques to deal with their negative responses.
One GP admitted to 'a heartbeat moment' when faced with a patient quoting from the web.
'Internet-informed patients proved challenging,' Dr Sanjiv Ahluwalia, a north London GP and lead researcher, wrote.
The shift in the balance of power means GPs have reshaped their role 'from gatekeepers of secondary care services to facilitators of information interpretation and decision making', Dr Ahluwalia said.
GPs expressed 'a sense of anxiety' when faced with a patient bringing internet information.
But an existing good rapport with the patient protected GPs against internet-related stress.
'The importance for doctors of feeling valued by patients was apparent, as was the effect of the prior doctor-patient relationship,' Dr Ahluwalia said.
GPs were frightened of losing control of the consultation. 'I am threatened by the possibility they have read something I don't understand,' one GP said.
But GPs played for time by asking open questions and adopting open body language. They got over their fear by admitting ignorance and showing respect for patients' information.
Members of the GP35, GP's panel of GPs aged under 35, echoed the findings.
Dr Manjiri Bodhe, a GP in Warfield, Berkshire, said: 'Sometimes you can get a sense of doom when a patient comes in with a printout.
'Sometimes it heightens their expectations and I feel I am fighting a losing battle.'
But she said it can really enlighten patients, and help the GP if their diagnosis is correct.
East Durham GP Dr Kamal Sidhu said printouts could cause anxiety, but data from trusted websites could help.
He added: 'A well informed patient means a shared management plan, which means more positive outcomes.'