A large number of parents have to say "no" to prescriptions for their kids.

A study shows that about 20% of prescribed medicine for children goes unfilled.

Amy Peak with Butler University's pharmacy program says in most of those cases, about 75%, it's because the parents can't afford the medication, but there are other reasons too.

Peak says often times doctors will write a prescription, but give kids sample drugs that make the healthy again.

Also, some parents just let nature take it's course, especially if their child shows signs of improvement after the visit to the doctor.