Sayyidah Rabi'ah bint Iyad al-Kilabiyyah (may Allah be pleased with her) narrates: I heard Sayyiduna Ali (may Allah be pleased with him) say: "Eat pomegranates with their pith, for they are a tanning for the stomach."
Ahmad recorded it, and its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأطعمة / 8041