Babies normally start teething when they are six months old. It is normal for teething to start at any time between 3 months and 12 months of age. By the time your child is about 3 years old, he or she will have all 20 primary teeth. During the teething child becomes cranky and fussy.
Child can become irritable as he/she can have gum swelling. Because of irritation of teething he/she puts things in their mouth due to which they can suffer with Diarrhea.