Regular Explression help

[loll]

I have an array of words, what I want is to make a regular expression that will find the words that contain ABC but dont contain any other letter in the alphabet.

So for example it would find BA and CAB but would not match BAT(because it contains a T)

Can I do like: ereg([abc^d-z) or something like that?

Thanks for your help

[Weedpacket]

^[abc]*$