What can cause bad breath after tonsils removal?

Tonsil stone. Is very common condition. Tonsil stones are irregularly-yellowish, very bad-smelling globs of calcium, collagen, mucus and bacteria that get caught in the back of the throat. Many small tonsil stones do not cause any noticeable symptoms. The larger stones can have a major symptoms like a constant bad breath, sore throat and earache. Remove the stone with waterpik. If concerned see ent.
Healing. It is common for there to be some bad breath after tonsils are removed because of the blood clots in the back of the throat. If this is your child healing will be quick. If this is for you healing will take a few weeks. Follow the post op instructions given by the surgeon.