Grapes are sweet and warm in nature. Grapes benefit the qi and blood and are suitable in cases of deficiency of qi and blood leading to a dry night cough with little or white phlegm. Any other kind of cough will be made worse by grapes. Grapes are also beneficial for palpitation and oedema caused by qi deficiency with low blood pressure, low blood sugar, fatigue etc People with diabetes or any kind of allergy should avoid grapes.