Major Marquis Warren: Move a little strange, you're gonna get a bullet. Not a warning, not a question...a bullet.
John Ruth: Music time's over!
John Ruth: One of them fellas'll kill everybody in here.
Oswaldo Mobray: The man who pulls the lever, that breaks your neck will be a dispassionate man. And that dispassion is the very essence of justice. For justice delivered without dispassion, is always in danger of not being justice.
John Ruth: No one said this job was supposed to be easy.
Major Marquis Warren: Nobody said it's supposed to be that hard, either.
Major Marquis Warren: When the handbill says "dead or alive", the rest of us just shoot you in the back from up on top a perch somewhere and bring you in dead over a saddle. When John Ruth the Hangman catches you...you hang.
Answer: It's not PURELY fictional, as plenty of poisons lead to vomiting and bleeding (cyanide, arsenic, etc.), but Tarantino, as is his wont, definitely takes some artistic license and kicks it up several notches for dramatic/gross-out effect.