Sayyiduna Hasan bin Ali (may Allah be pleased with them both) took a date from the dates of charity and ate it. The Prophet (peace and blessings be upon him) said: "Kikh, kikh!" so that he would throw it out. Then he (peace and blessings be upon him) said: "Do you not know that we do not eat charity?"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13231