After a cold, the body’s resistance decreases, and bacteria often take advantage of the situation. Therefore, when the fever does not go down after several days of cold and there is pus sputum coughing, you should pay attention to the mixed infection of bacteria and go to the hospital in time to prevent it from turning into bronchitis. The symptoms of a cold are very similar to those of many diseases at the beginning, but they are very different, so you should not take them lightly. If the fever is accompanied by severe nausea and vomiting and recurrent episodes, then brain lesions (such as meningitis) should be suspected. If you have a fever, do not want to eat fatty food, and have symptoms such as nausea and vomiting, you should suspect a reaction to infectious hepatitis. The virus in the flu can sometimes cause myocarditis, and the symptoms are often panic, chest tightness, shortness of breath, and vague pain in the precordial area a week after the flu, especially when the heart beats too fast, more than 100 times a minute. If your heartbeat is irregular, you should go to the hospital promptly. If the onset of the disease is very rapid, chills, then fever, and high fever does not go away, often above 39 ℃, body aches and pains, no appetite, and people around the same performance, then it is suspected of influenza. If the fever does not go away, and is accompanied by breathing difficulties, coughing, and purple lips, then pneumonia is suspected. If a child is crying and does not want to eat, and has a red and swollen throat, or even white pus spots, tonsillitis should be suspected. If a child has a fever until the second day and begins to have small red papules on the face and body that are densely and evenly distributed, with a bright red tongue and pale circles around the mouth and lips, it is possible that the fever is scarlet fever. On the fifth day of fever, a red rash appears on the body, the liver and spleen are enlarged, and there is confusion, so it may be typhus. If you have a fever in the afternoon but not in the morning, and you also have symptoms such as weakness, dry cough, night sweats (cold sweats), and are losing weight, you may have tuberculosis. If you have any of these conditions, you should go to the hospital promptly and do not buy medicines at will.