Can seafoam do any damage to an engine?

I have a 23 year old ecotic V6 4.3 letter engine. I recently used seafoam on a 8 year old engine in the oil as a cleaner and I could not be happier! I gained roughly 10% power back that I didn't realize I lost. Can anyone see any harm with using seafoam on an older engine? I just don't want to use it, then just to have all the seals start leaking.