As the title, Buddha died of Bloody diarrhea? Because it is confusing that Buddha died in cancer here but I cannot manage to find any source. The only reference I found is Mahāparinibbānasutta and it does not specify that any cancer or cancer related disease in pali text. And Buddha clearly mentioned that the last deadly cause was not because of last meal (neither pork nor mushroom) in that sutta.
The pork of the last meal was indeed deadly:
DN16:4.19.3: I don’t see anyone in this world—with its gods, Māras, and Brahmās, this population with its ascetics and brahmins, its gods and humans—who could properly digest it except for the Realized One.”
But, the Buddha surrendered the life force before he ate the last meal:
DN16:3.37.4: So today, just now at the Cāpāla tree shrine, mindful and aware, I surrendered the life force.”
Notably, before the Buddha surrendered the life force, he gave Ananda a remarkable opportunity:
DN16:3.3.2: The Realized One has developed and cultivated the four bases of psychic power, made them a vehicle and a basis, kept them up, consolidated them, and properly implemented them. If he wished, the Realized One could live on for the eon or what’s left of the eon.”
However, once the life force was surrendered, that opportunity vanished:
Here, the pivotal event is surrendering the life force, not the meal. This may sound strange, but it is a fact that people tend to die on specific days (i.e., close to their birthday). Cancer cells don't really care about birthdays, so something else is involved. Let's just call it "the life force".
So, although the pork was deadly, the life force was surrendered before the meal.
Why does this matter to you? If this question is based in some attraction to lurid information, it's not really consistent with Buddhist practice. Would Buddhist teachings be 'better' if we discovered that the Buddha had been (say) eaten alive by wild hyenas, or drowned in a river, or tossed out a window by an angry king, or just died peacefully in his sleep? Would that change his teaching, or the practice, or anything else?
An unfocused mind is easily distracted by bright and vulgar thoughts. Don't worry about the thought, but recognize the distraction for what it is.