Firstly, the other entry you got, pointing you at HTML::Entities, is without a doubt the right way, if you are looking to solve the problem. On the other hand, you have looked at it, and rejected it for good reason (which here includes "because I already did it that way and want to try doing it other ways as well"), some advice on how to do it more or less the same way, but better...

s(&#(.*?);){
 code goes here
}eg;
[download]

is how I'd write that. The change to (.*?) instead of ([^;]+) is a matter of asthetics, and a somewhat contriversial one. It makes the regex somewhat slower, possibly, but it avoids repeating the exit condition. Putting on the /g is a matter of correctness -- consider <foo>. Note that you don't want to apply the regex to the same data in a loop -- consider &. The /e is to let the replacement thingy be code... what code I'm going to leave as an exercise to the reader.