Hi Rie, my understanding is that when a child is oversuppressed, getting to much medicine, they can have weight problems. As well, when a child is undersuppressed, not getting enough medicine, they can have problems putting weight on and may be quite thin. As for your son not liking taking pills, you could try crushing them either with a pill crusher or between 2 spoons. Some parents disolve the pills in apple juice and then squirt them into the childs mouth with a syringe. Hope this helps.