The first rule of being a doctor is to do no harm. Unfortunately for we in the non-medical community, not every doctor upholds this rule as well as we would like. And in the magical world of the movies, there are even more doctors willing to inflict harm not only on their patients, but on any innocent passerby that get in their way. Just in time for you to update your insurance coverage, here are six movie doctors who will do harm.

Dr. Caligari, "The Cabinet of Dr. Caligari"

Rather than using his talents in the medical field to treat disease and better mankind, Dr. Caligari chooses to confine a young man to a coffin where he is forced into a hypnotic coma, only to be awakened to do the doctor's murderous bidding. We're pretty sure that's not covered in his HMO! But seriously, he's a menace. And even though this movie was made way back in 1920, it still has the power to terrify viewers.

Dr. Jekyll, "Dr. Jekyll and Mr. Hyde"

Here's a case of a classic film doctor who will do harm despite his good intentions. All Dr. Jekyll wanted to do is separate the evil side of his mind, isolate it, and put it away where it can't do anyone any harm. That ... didn't work. Instead, it turns Dr. Jekyll into the murderous Mr. Hyde. Still, it's safe to say that Dr. Jekyll has done harm in this particular case, especially as far as the courts are concerned. That whole "evil transformation due to potion" does NOT work.

Dr. Phibes, "The Abominable Dr. Phibes"

Here's a movie doctor that takes "doing harm" to an entire new level. After a team of nine surgeons failed to save his wife after a car crash, the good doctor (whose doctorates happen to be in the fields of music and theology) begins an elaborate scheme of revenge, murdering the surgeons one by one in accordance with the plagues of Egypt. He even took the liberty of making up a couple plagues in order to make it work. That's what you call medical license!

Dr. Szell, "Marathon Man"

Imagine the most evil Venn diagram you can, showing the overlap between "evil dentists" and "Nazis." Right there in the middle is Dr. Christian Szell, who was known to perform brutal experiments on his victims during the Holocaust. In the movie "Marathon Man," he comes out of hiding in South America to claim a large fortune, and in order to get that fortune, he feels he needs to torture poor Dustin Hoffman. He does this using, you guessed it, dentistry. Is it safe? Definitely not.

Dr. Frank-N-Furter, "The Rocky Horror Picture Show"

This cult movie doctor's ability to do harm is a little more nuanced than the others. And you can assume that "nuanced" means "completely incomprehensible." His scheme involves capturing innocent people and, uh, singing for them. Trust us, though, you don't want Frank-N-Furter to be your primary care physician. The guy's made, he says it right in the song!

Dr. Hannibal Lecter, "The Silence of the Lambs"

Pretty much the definitive movie doctor who will do harm, Hannibal "The Cannibal" Lecter will mess you up in ways that aren't polite to even describe in mixed company. The scary thing about Lecter is that he's really smart, even by doctoral standards. He's physically formidable, too, able to overpower security guards and police officers even though he's outnumbered. Oh, and he eats people. Doctors aren't supposed to eat people!

These six movie doctors who will do harm may have earned their PhDs, but that doesn't mean they're to be trifled with. They're diabolical, often violent and definitely unstable. Bad doctor!