Can headache patients eat watermelon to relieve summer heat?
Generally speaking, if the headache is a common tension-type headache or a mild headache caused by hot weather, eating watermelon can help relieve heat. However, if the headache is caused by dysfunction of the central nervous system in the brain, it is not advisable to consume watermelon for heat relief. The detailed explanation is as follows:

If the headache is a common tension-type headache or a mild headache caused by hot weather, eating watermelon is acceptable. Watermelon contains abundant water and electrolytes, which can help replenish fluids and minerals lost due to high temperatures, thus helping to relieve heat. At the same time, the vitamin C and antioxidant substances in watermelon can help alleviate inflammation and stress, assisting in reducing headache symptoms. However, it should be consumed in moderation to avoid digestive problems caused by excessive intake.
If the headache is caused by dysfunction of the central nervous system due to a generally weak constitution, watermelon, being a cold-natured fruit, may exacerbate the dysfunction of the central nervous system and worsen the headache. Additionally, because watermelon has a high water content, consuming it may increase urination, which could disturb the patient's rest. Headache patients usually require ample rest, so increased urination may hinder recovery and even worsen headache symptoms.
Headache patients should maintain a light diet and avoid consuming spicy or irritating foods to prevent aggravating their condition.