I've never been on it..
But the most common side effects for this is (and remember not everyone gets side effects)
Headache, upper respiratory tract infection, stomach ache, vomiting, loss of apeitite, sleeplessness, increased cough, sore throat, sinusitis, and dizziness.
The rare side effects are... ticks, "zombie" demeanor, moodiness...
There is more information, if you want to read up on it here is the website.
http://www.adhdhelp.org/concerta.htm
<font color=red>~Sundance~</font color=red>
<font color=blue>"Never react emotionally to criticism. Analyze yourself to determine whether it is justified. If it is, correct yourself. Otherwise, go on about your business."</font color=blue>
<font color=black>Norman Vincent Peale</font color=black>