It is narrated from Sayyiduna Salman bin Amir al-Dabbi (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When one of you breaks his fast, let him break it on dates; and if he does not find any, let him drink water, for it is purifying."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6169