Bad breath in toddlers can be caused by poor oral hygiene, but it can also be caused by periodontitis and Helicobacter pylori infection. 1. Unclean oral hygiene: If a toddler’s oral hygiene is not done properly, it may lead to bad breath in toddlers. Parents are advised to pay attention to their children’s oral hygiene, brush their teeth in the morning and evening, and rinse their mouths after meals. 2. Periodontitis: If a child has teeth erupting, inflammation around the dental tissues may also lead to bad breath. 3. Helicobacter pylori infection: If the parent and child do not eat separately, the child may get Helicobacter pylori from the parent. The typical symptom of H. pylori infection is accompanied by bad breath. There are many causes of halitosis in young children, so parents are advised to bring their children to the doctor in time to find out the cause and then treat them actively.