It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "The blood of a menstruating woman comes in several gushes (daf'at), and menstrual blood has a smell that no other has. So when the period of menstruation has ended, let each of you take a ritual bath (ghusl), then wash the blood off herself."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11465