It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said concerning a man who had intercourse with his wife while she was menstruating: "If the blood is fresh red, he should give a dinar in charity; and if it is yellowish, then half a dinar."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12083