Why is it black after eating pig blood?

After eating pig blood stool is black, mainly consider and pig blood components, pig blood contains a certain amount of iron, so it will show stool color change. Eat pig blood stool black normal recovery in two days or so, if two or three days later do not eat pig blood, stool or black, then this situation is the need to go to the hospital to check, the main screening is not gastrointestinal bleeding. Do not eat pig blood stool after the recovery of that do not worry about it.