Medics on the social networking site Facebook could be threatening the doctor-patient relationship, according to experts.
A study of more than 400 trainee doctors found most of the 73 per cent with a profile displayed enough personal information to be identified.
This includes real name and date of birth, while 91 per cent had also put up a photo of themselves.
More than half had provided information on their current job title and 59 per cent provided details of university medical training.
Some 61 per cent thought they had changed their privacy settings to prevent people seeing most of their details but 17 per cent could not remember exactly.
Doctors who had been on Facebook for less than a year were less likely to limit access to the content of their profile.
Of those surveyed, from Rouen University Hospital in France, only six per cent had received a Facebook request from a patient and only four had accepted the request. However, the authors, writing in the Journal of Medical Ethics, said such requests will become more common.
While most doctors (85 per cent) said they would automatically refuse a friend request from a patient, one in seven (15 per cent) said they would decide on a case by case basis.
This might be because they feel an affinity with them or fear embarrassing or losing the patient if they declined.
Reasons given for declining a friend request included the need to keep a professional distance or suspicion that the patient was interested in a romantic relationship. But such a relationship being unethical came bottom of the list of reasons.
But the authors said: "This new interaction (whether it is romantic or not) results in an ethically problematic situation because it is unrelated to direct patient care.
"Moreover public availability of information on a doctor's private life may threaten the mutual confidence between doctor and patient if the patient accesses information not intended for them.
"Doctors must be aware that comments and pictures posted online may be misinterpreted outside their original context and may not accurately reflect their opinions and real-life behaviour.
"This information could also become accessible to people that it was not intended for."