Neil Patrick “Doogie Houser” Harris and other actors who’ve famously played doctors on TV recently collaborated on a commercial to encourage folks to get an annual check-up. At least these actors are upfront and honest about the fact that they’re not real physicians. But what about some other famous people who have long presented themselves with a “Doctor” in front of their names? Have you ever wondered about their credentials?

Photo Credit: Fox

Dr. Oz

Mehmet Oz is indeed a heart surgeon; his degree is from the University of Pennsylvania School of Medicine. He also is the vice-chairman of the Department of Surgery at Columbia University, which doesn’t sit too well with some of his colleagues. In 2015 ten fellow surgeons at Columbia requesting Dr. Oz’s dismissal, citing his “disdain for science and evidence-based medicine.” In other words, they’re none too happy about Dr. Oz’s propensity to promote things like green coffee beans and African mango seeds as possible cures for everything from obesity to Alzheimer’s disease.

Photo Credit: Instagram, @dr_oz

Dr. Laura

Over seven million listeners tune in daily to hear Dr. Laura Schlessinger preach and teach about her version of good old-fashioned morals and values. Although Dr. Laura occasionally refers to herself as a “shrink,” she has neither a medical degree nor a psychology degree. What she does have is a PhD in physiology from Columbia University – a degree that has nothing to do with interpersonal relationships, but does qualify her to teach physical education at the college level. (Pity the awkward overweight student in that class.)

Photo Credit: Instagram, @drlauraprogram

Doc Marten

The favorite footwear of punks and skinheads was, in fact, invented by a bona fide physician. Klaus Maertens graduated from medical school in Munich in 1942 and served as an Army doctor in his native Germany during World War II. He was granted a leave in 1945, and he treated himself to a skiing holiday in the Alps. Unfortunately, he injured his ankle, and his military-issue boots made the pain worse, so he tinkered with the design and came up with his now-patented, soft leather, extra cushioned boot.

Photo Credit: Instagram, @drmartensofficial

Dr. Seuss

After getting his undergrad degree at Dartmouth (despite a brief period of probation after being caught drinking gin in his room with friends), Theodore Seuss Geisel attended Lincoln College at Oxford University with the intent of obtaining a PhD in English. He eventually realized that he enjoyed doodling cartoons much more than studying Shakespeare, which led him to drop out of college before finishing his degree. He added the medical honorific to his name anyway in order to please his father, who had always hoped to brag to friends that his son was a doctor. Geisel did, however, receive an honorary doctorate from Dartmouth in 1955.

Photo Credit: Wikipedia

Dr. Bronner

Emanuel Heilbronner, the literal guru behind a line of castile soaps with rambling religious messages on the bottle, was born in Germany to a family of soap makers. He emigrated to the United States in 1929 and shortened his surname to avoid the Nazi association with “Heil”. Bronner was never a doctor, and even though the official biography on the Dr. Bronner’s website mentions him obtaining a “university degree in chemistry,” there is no record of him having ever attended any university.

Photo Credit: Wikipedia

Doc Holliday

Old West gunfighter John Henry Holliday earned his nickname by virtue of being a dentist. He graduated from the Pennsylvania College of Dentistry in 1872. When he was diagnosed with tuberculosis he was advised to move West, to a dryer climate, so he opened a practice in Dallas. Unfortunately, dry air doesn’t cure TB, and his wracking coughing spells forced him to give up dentistry. His natural intelligence proved to be an asset when it came to playing poker, and he supported himself by becoming a professional gambler. He also befriended Wyatt Earp along the way, which is how he eventually became involved in the famous shootout at the OK Corral.

Photo Credit: Wikipedia

Doc Severinsen

Back when Johnny Carson hosted The Tonight Show, his flamboyantly-dressed band leader was “Doc” Severinsen. Born Carl Severinsen Jr., Carl’s father was a dentist, and family and friends called the young boy “Little Doc” in order to differentiate between him and Carl Senior. Even though his dad urged him to study the violin, Little Doc took up the trumpet at age seven. Five years later he won top honors at the prestigious Music Educator’s National Contest. (Lest you think Doc was an ancient lounge-lizard-type relic by the time the ‘90s rolled around, watch him lead the band and perform with They Might Be Giants on their classic quirky hit “Birhouse in Your Soul”.)