Byakogou will cause healthy cells to split. No reason to believe poisoned cells are going to rapidly multiply because if that was the case, all sorts of nasty cancerous cells would start splitting whenever Byakogou is used, causing cancer. Thus it can be concluded that Byakogou causes only healthy cells to split because anything other than that would contradict the purpose of what is hailed to be the ultimate medical ninjutsu.
The rapid splitting of healthy cells should mitigate the effect of the poisoned cells but poison won't be removed from the body through this process. As a result, being poisoned would cause great strain for a Byakogou user but the effects of the poison will be greatly slowed down.
The rapid splitting of healthy cells should mitigate the effect of the poisoned cells but poison won't be removed from the body through this process. As a result, being poisoned would cause great strain for a Byakogou user but the effects of the poison will be greatly slowed down.