Smelly poop in infants may be caused by indigestion, gastrointestinal dysfunction, enteritis and other reasons. 1. Indigestion: usually when babies have indigestion, it will also lead to smelly poop. 2. Gastrointestinal dysfunction: because the gastrointestinal function of infants is not well developed, getting cold at night or eating too cold food will lead to gastrointestinal dysfunction, which will lead to smelly feces of infants. 3. Enteritis: usually some bacteria or viruses, such as infant rotavirus infection and some pathogenic bacteria, can cause enteritis, which can lead to smelly stool, diarrhea and other symptoms. There may be many other reasons for infants’ smelly poop, parents are advised to bring their infants to the doctor actively to find out the cause of the disease and then carry out standardized treatment.