Yusupov and his accomplices had planned things carefully. The cakes offered to Rasputin had been laced with enough potassium cyanide to slay a monastery full of monks. But Rasputin just kept eating them. Incredulous at the monk’s survival, Prince Yusupov poured madeira into a cyanide-laced wine glass and handed it to Rasputin. Instead of collapsing into unconsciousness within seconds, as would be expected from a massive dose of cyanide, Rasputin continued to sip the wine like a connoisseur. A second lethal glass disappeared into the monk’s mouth with little apparent effect other than some difficulty swallowing. Asked if he was feeling unwell he replied “Yes, my head is heavy and I’ve a burning sensation in my stomach.” A third glass of tainted wine only seemed to revive him. Having ingested their whole stock of cyanide, the group of assassins were somewhat at a loss as to what to do next.
The various possibilities on the cyanide are good hypotheses. Indeed, two of my friends who took cyanide drank grapefruit juice first to be sure the cyanide dissociated. Even if Rasputin didn't have alcoholic gastritis, perhaps the cakes served as a buffer to the stomach acid.
But the recently revealed autopsy results claim that poison wasn't detected in his stomach, FWIW.
