I have noticed this is in both my children. I was giving tylenol to my son, 4 years old, when he would complain of leg cramps, thinking it would ease his pain and help him sleep. Instead he would cry all through the night, I would put him my bed and he would still wake up crying and in the morning he wouldn't remember anything about it. I thought it was because his pain was returning and that is why the crying persist and figured he was just tired as to why he didn't remember anything. Then the past two nights my daughter, who's 1 1/2 years old, was running a fever I gave her a half dose the first night and she woke up once crying and wouldn't close her eyes for about hour after I laid her back down, then last night the fever was still there so I gave her a full dose. She woke up every hour SCREAMING! She would sit straight up in bed and scream at the top of her lungs, it was horrible. I haven't had any professional tell me it is because of the Tylenol but I am pretty sure it is the reason for both of my children's restless nights. -The bottle is in the trash now!