OnTriggerEnter

That should work? Are you calling it as you pasted it with the semicolon? That's the only issue I can see that it should be followed by brackets, because it is simply defined and called when things enter it, not anytime else. That said, it's always possible you just absent-mindedly put it there, in which case what I suggested isn't exactly a fix. Either way, you'd be better off getting a solid answer by maybe including some more relevant code surrounding it to give a better understanding for people trying to answer.