I always feed mine right when they open, and they are happy that way. I don't have any idea why their would even be a problem at all, In fact, I would think it would prefer to be fed. That is stomic acid sitting in it's traps you know, lol!
(side note)
Medical uses? Ewww, no thanks, I'm not into narcotic stumic juice, what is it used for? Sterilizzing wounds?