In the fall and winter, the high incidence of pediatric diarrhea, along with the baby’s vomiting and defecation, the parents began an anxious trip to the emergency room. 8-month-old Meng Meng vomited and had diarrhea for 3 days, with pale, depressed, sweaty, and cold hands and feet, and was carried to the emergency room by her parents, who were informed by the doctor after a careful physical examination combined with laboratory results that the child’s heart rate was significantly increased, with irregular rhythm, low heart sounds, and a weak pulse and elevated cardiac enzymes. The doctor said that the child’s heart rate was significantly higher, his rhythm was irregular, his heart sound was low, his pulse was weak, his cardiac enzymes were elevated, and he might be suffering from viral myocarditis and needed to be hospitalized as soon as possible. The first symptoms are very similar to those of an intestinal infection, which we usually think of as diarrhea, but after that, severe cases can develop arrhythmias, heart failure, cardiogenic shock, and even sudden death. The symptoms that children exhibit are mainly weakness, easy sweating, depression or irritability, shortness of breath, weak pulse, cold hands and feet, and some children with severe disease may experience inability to lie down, repeated syncope, and convulsions. However, early and mild viral myocarditis often has no obvious symptoms, and small children do not complain, making early detection and diagnosis somewhat problematic. Therefore, when your baby has symptoms such as weakness, easy sweating, depression or irritability, shortness of breath, and a weak pulse after diarrhea, you must go to the hospital as soon as possible so that your child can have an electrocardiogram, cardiac ultrasound, cardiac enzymes, chest X-ray, and other tests to determine if your child has viral myocarditis.