the first thought that pops into my mind is "how often are we talking about and is it the children’s version? " tums makes a product for children but there are specific instructions on how and when to use them. this should not be a "usual" situation and i would recommend bringing this up with the doctor or health care provider for further evaluation.
my wife gives my 3-year-old son tums when he claims to have a stomachache. is it good/safe to give it to him?