GPs must exercise extreme caution in making entries on social networking sites, medical defence experts say.
A 'very rapidly growing' number of doctors have fallen foul of constraints to behave in a professional manner.
The charge extends to doctors who make disparaging remarks or identify patients on doctors-only websites.
Doctors who make 'intemperate, disparaging or inappropriate remarks' on sites such as Facebook and MySpace can find themselves before the GMC even if they do not divulge their professional identity.
'Once information has been taken out of context, it's easy to check your identity with the GMC,' said Dr George Fernie, medico-legal adviser with the Medical and Dental Defence Union of Scotland (MDDUS).
'In the past year we have had several cases resulting in us having to protect our members at the GMC,' he said.
A GMC spokesman said: 'We don't monitor Facebook but we do pick up cases from letters or articles in the press.'
A social networking site case has yet to come before a fitness-to-practise panel.
But a junior doctor was suspended last year after making 'scatological' remarks about Dame Carol Black, DoH director for health and work, on the website Doctors.net.uk.
Last week a GP identified a patient on a doctors-only website, exposing themselves to a charge of breaching patient confidentiality, GP has learned.
Meanwhile, the MDDUS is warning GPs not to overstep professional boundaries by being too helpful to patients.
An article appearing in this week's GP warns that extra help such as driving patients to appointments can create legal problems.
There are exceptions, however. GPC chairman Dr Laurence Buckman told GP he once drove a patient to hospital when the ambulance did not turn up because he feared they would die.
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