1. Testicular inflammation: commonly occurs about a week after mumps, with sudden onset of high fever, chills, testicular swelling and pain with severe tenderness, significant scrotal skin edema in severe cases, yellow fluid in the sheath cavity, lesions mostly invade one side, acute symptoms about 3 to 5 days, the whole process about 10 days. Rarely leads to infertility. 2. Ovarianitis: The main manifestations are sudden onset of chills and fever, pain in the lower abdomen or lumbosacral region, menstrual cycle disorders, and in severe cases, enlarged ovaries with pressure pain can be palpated. It does not affect fertility. 3. Pancreatitis: It often occurs about 1 week after swelling of the parotid gland, with severe pain and tenderness in the upper and middle abdomen and muscle tension as the main symptoms. It is accompanied by vomiting, fever, abdominal distension and constipation, and sometimes an enlarged pancreas can be found. 4. Meningitis or meningoencephalitis: clinical manifestations are acute high fever with severe headache, vomiting, drowsiness or impaired consciousness, positive signs of meningeal irritation, etc. Cerebrospinal fluid examination all show changes of viral encephalitis or meningitis. The prognosis is generally good, but individual severe cases can lead to death. 5. Myocarditis: Most often seen in the course of the disease 5-10 days. It is characterized by pallor, increased or slow heart rate, low heart sounds, arrhythmia, and temporary heart enlargement. Systolic murmur. Sinus arrest, atrioventricular block, ST-segment depression, and low or inverted T waves are seen on the electrocardiogram. Severe cases can be fatal. However, most of them only have ECG changes without obvious clinical symptoms. Occasionally, there is pericarditis. 6. nephritis: mumps virus can be isolated in the urine in the early stage, so it is believed that mumps virus can directly damage the kidneys, with a small amount of protein in the urine in mild cases and the same performance as acute glomerulonephritis in severe cases. However, most of them have a good prognosis.