Naruto Shippuuden Episode 47

[Abdula]

I don't know if this was mentioned before but I think the reason why Oro's body keeps rejecting him after a while is because this is Oro's temporary method of immortality. Meaning, as long as he keeps switching bodies, he can live forever. I think it was hinted out when we saw that woman's face as the inner Oro during the fight with the 3rd. Not too sure but there just seems no other explanation why his body keeps rejecting him and he has to keep going through the hassle of obtaining new bodies.

What do you mean why his body keeps rejecting him. This is the first time we have seen any of Oro's host bodies start rejecting and I believe that is simply because he didn't have anytime to prepare it, as he was completely focused on Sasuke at the time. He went into this body out of desperation. Besides didn't Oro leave the village about some 20 odd years ago and when he met the third he told him that girl was only his second body so he most definitely can stay in a body for more than three years.