I am SO sick at my stomach right now after reading all of these posts. My son is 2yrs old and was put on Singulair right after the new year. We have noticed a horrible change in his behavior....but we attributed it to his age and the fact that he is VERY strong-willed. However, thinking back, he has had some hallucinations. We had a babysitter tell us that when she tried to put him to bed that he cried and told her that there were monsters in the closet. When she picked him up and took him in the kitchen for a drink he kept reaching at the ceiling trying to grab something. Just last night he told me that he saw his Grammy dancing in the living room....my Mom wasn't even there. He has been throwing horrible fits to the point of gagging himself, hitting himself, kicking, hitting, screaming....you name it. At the end of them, I am usually in tears and we are both exhausted. I am not the only one who has experienced this with him....my Mom has too. He is also on Veramyst nose spray....both meds are for allergies. We have taken him off of both and decided to go a more natural route. We have bought local honey, an immune booster from teh health food store, and have him on a really good brand of liquid vitamins. It is hard as a parent to make decisions about your child. It is even worse when you realize that the decision you made has affected your child in a horrible way. I plan on giving him A LOT of attention tonight and giving him a big hug! I just want my fun, playful son back! Good luck to all of you and God Bless!