Are Constants a safe place to store things like the Administrator's E-mail Address?

I am looking for a way to streamline my PHP Error-Handling, and would like to have One Variable/One Place where I can store things like the Admin's E-mail.

If I put it into a PHP Constant, then it would accessible to all of my scripts, which seems like a good thing. However, maybe that is bad from a *security* standpoint?!