Sayyiduna Uqbah bin Amir al-Juhani (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "When one of you applies kohl, let him apply it an odd number of times; and when he uses stones (after relieving himself), let him use an odd number."
Ahmad recorded it. Its chain contains a narrator, Ibn Lahi'ah, whose hadith is hasan (good); the remaining narrators of this report are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطب / 8354