As a physician, I see no recourse that I could take if a patient decided to make a libelous statement about me. Someone could write something, but I couldn't write a rebuttal without violating patient confidentiality. Say someone posts something like "Dr. Magic_Dude was arrogant, rude, didn't address my concerns, and insulted me before throwing me out", I couldn't say "Just before this comment was posted, Mr. Johnson came to visit me as a new patient asking for Oxycontin. After discussion with his prior physician, I learned that he has a history of narcotics abuse, and has severe bipolar disorder. When I refused to fill his prescription, he stormed out of my office. He also required treatment for gonorrhea during his visit." Essentially, in order to defend your actions to the best of your ability, you would be required to break confidentiality. If anything, I would say physicians should change the contract saying that if you're going to start posting your medical encounters on the internet for all to see, then you waive your right to confidentiality and permit rebuttal by your practitioner.