In its new draft guidance, the doctors are warned to be extremely careful and remind them that the relationship would usually be considered inappropriate.
In a move that nullifies the past prohibition, the guidelines acknowledge that social circumstances may demand that the relationship be made permissible. However it cautions that the professional relationship must have ended.
The GMC pointed out that the existing guidance for doctors was 10 years old and was devoid of clarity.
Jane O'Brien, the head of standards at the GMC, said the existing guidance demanded that doctors should not misuse their professional position to establish or pursue a sexual or improper emotional relationship with a patient or someone close to them. There was no specific guideline advising them on relationships with former patients.