The main thing of interest to me in this short, which is only interesting in hindsight and would not be interesting upon release, is how animated Buster is in this one. He plays a child who gets pushed around a lot and does these wonderful acrobatic falls. I love the way Roscoe pushes Buster, making him somersault on a table and land perfectly seated in a chair. We all know Buster can take a fall, so what is most interesting is the cries and hamfisted mugging Buster does. The Arbuckle films are the only films where he's not deadpan in his demeanor, but OH, DOCTOR! is easily Keaton at his most ham fisted. That to me is the standout of this film.
The rest of it, not much else to say. Well made in terms of story, and I agree with Big Chief for the most part that most of the humor lies in the acrobatics. I also must echo the thoughts about the car scene being good as well as the witty ending of how Arbuckle got the money, but the majority of this is good, if not great standard slapstick. The chase is like comfort food, but again, not quite at the level of Buster and Harold chases of the 20's. A shame Arbuckle truly never got a chance to compete with those guys, it would of been interesting to see how he developed. Want to add the idea of injuring people as a doctor to try to build more patients was done in a much more developed way in Harold Lloyd's classic NEVER WEAKEN.