It is narrated from Aisha (may Allah be pleased with her) that Umm Habibah bint Jahsh (may Allah be pleased with her) suffered from istihada (non-menstrual bleeding) for seven years. She asked the Messenger of Allah (peace and blessings be upon him), and he said: "This is a vein, not menstruation." And he instructed her to perform ghusl and pray, so she would perform ghusl for every prayer. She would sit in a tub for ghusl, and the redness of the blood would appear on the water.
Hadith Referenceمسند الإمام الشافعي / كتاب الطهارة / 112
Hadith Takhrijأخرجه البخاري، الحيض، باب عرق الاستحاضة (327) ومسلم: الحيض ، باب المستحاضة وغسلها وصلاتها: (334)