It is narrated from Hazrat Umm Habibah (may Allah be pleased with her) that once she came to the service of the Prophet (peace and blessings be upon him) and complained about the continuous flow of menstrual blood. The Prophet (peace and blessings be upon him) said to her: "This is not menstruation, it is blood from a vein, so you should perform ghusl (ritual bath)." Thus, she used to perform ghusl at the time of every prayer, and when she would come out of the tub, we would see the color of the water as red.