Hepatitis B immunoglobulin does not usually cause diarrhea in infants, and diarrhea is not a common side effect of Hepatitis B immunoglobulin, so it is not a normal condition. Considering the infant’s young age, the gastrointestinal tract is not yet well developed, which may be caused by indigestion, gastroenteritis and other diseases. If the mother has hepatitis B, the infant needs to be immunized with hepatitis B immunoglobulin promptly after birth to reduce hepatitis B infection in the infant. Infants who have received hepatitis B immunoglobulin may have fever, redness and swelling at the vaccination site, but it does not cause diarrhea. Therefore, diarrhea in infants may not be caused by hepatitis B immunoglobulin. 1. Normal physiological conditions: considering the age of infants, the gastrointestinal function is not yet well developed, generally with the growth of age, diarrhea can be improved. 2. Dyspepsia: mainly related to improper diet, if breastfeeding, the mother is considered to be the intake of spicy stimulation of cold food caused by. 3. Gastroenteritis: the child will have diarrhea, abdominal pain, nausea and other symptoms, mostly due to acute infection. It is not normal for infants to have diarrhea after hepatitis B immunoglobulin, so parents are advised to take their children to the hospital for examination and clear diagnosis.