text: why is my blood black on the first day?   call a nurse and she will tell you this trust me its called old blood its normal at times when from the last time you stopped your period you didn't shed all of the blood and well the blood will be black on your first few days of the next period its normal lots of women do this so many times in there life that it just becomes a normal sight but it goes back to the normal color in a few days sometimes it will last tell your last day then that last day it will be red again its normal and you just collected all your blood early on in between the last period and this one is all.