“Once a woman came to abu ’Abd Allah (a.s.), and asked about the case of a woman who experiences blood discharge which does not stop and she does not know whether it is Hayd (menses) or something else. He (the narrator) has said that he (the Imam) then said, ‘Blood discharged because of Hayd (menses) is hot, thick and of black color. It comes with pressure and hotness. Blood discharge because of Istihadah (irregular menses) is of yellow color and cold. If blood discharged is hot, comes with pressure and it is of black color, she must stop performing Salah (prayer).’ He (the narrator) said that she left saying, ‘By Allah, were it a woman she could not explain it any better than what he (the Imam) did.’”