It is best not to eat crab when you have a fever. When you have a fever, your body heat increases and you are seriously lacking in water, so you need to replenish enough water to help dissipate the heat and to help your body temperature return to normal. Crab is a seafood food, which is cold in nature. Eating crab when you have a fever will affect the normal function of the stomach and intestines, resulting in diarrhea, vomiting, and even allergies, and will aggravate the fever, which is not conducive to the improvement of the disease. If the fever is caused by digestive system diseases, it will aggravate the symptoms of the disease. When a person has a fever, it is best to eat a liquid or semi-liquid diet, drink as much water as possible, and when the body temperature is high, antipyretic drugs need to be given in time for treatment, and it is not only impossible to eat crabs when you have a fever, but also not to eat high-calorie foods such as dog meat and mutton. A reasonable diet is good for the treatment of the disease.