An Nasa’y and Ibn Majah narrated in their Sunan that A’esha said that the Messenger of Allah said:
“Eat fresh dates with dried dates, for when Satan sees the son of Adam eating fresh and dried dates he comments, “The son of Adam remained until he started eating the new and the old together.”
In another narration, the Prophet said:
“The fresh and dried dates, because Satan gets sad when he sees the son of Adam eating them, so he says: The son of Adam has lived until (now) he eats the fresh and the old together.”
Some of the Muslim doctors commented, “The Prophet ordered the Muslims to eat fresh and dried dates together rather than green dates with dried dates. Fresh dates are cold and dry while dried dates are hot and humid, thus neutralizing the effect of each other. On the other hand, green dates and dried dates are both hot, although the dried dated are more hot.”Medically, it is better to avoid eating two types of foods that incline towards either hotness or coolness.
The Hadith indicates that the medical profession is generally correct when it inclines towards neutralizing the effects of medications and foods with other ingredients or foods to preserved good health.
Fresh dates are cold and dry and they benefit the mouth, the gums(gingiva) and the stomach. Yet, dates are not beneficial for the chest and lungs because of their coarseness. In addition, the dates are difficult to digest and are not very nutritious. The example of fresh dates is the example of unripe grapes, as both cause flatulence and bloating, especially when one drinks water after eating fresh dates. To neutralizi these side effects, one should eat them with dried dates, or honey and butter.