Dr. Murray Wants to Bar Testimony Casting Doubt On Swallowing Propofol

Dr. Conrad Murray's lawyers want to ban a prosecution medical expert from testifying that ingesting Propofol would not trigger a fatal reaction.

TMZ broke the story months ago ... the defense will argue ... a frustrated Michael Jackson accidentally killed himself by either ingesting or injecting himself with a fatal dose of Propofol when Dr. Murray left the room.

Prosecutors intend to call Dr. Steven Shafer, who embraces two studies which allegedly conclude a patient can't die from orally ingesting the drug.

In one of the studies, 6 Chilean students volunteered to drink Propofol -- and they survived just fine.

Another study produced the same results, but the patients were pigs -- real pigs.

Dr. Murray's team claims the studies are hearsay, because Dr. Schafer wasn't part of the tests.