Our Ives had stones throughout his urinary tract (poor guy - he must have been in extreme discomfort for quite some time - ferrets are way too stoic!). Too make a long story short, the vet had to back flush him to remove all the stones (from penis to bladder). He was in surgery for almost two hours. Now to the point. The vet rerouted his urethra to a new opening just under his anus - in effect making a girl out of the poor guy. Removing the penis was NOT necessary, just sealing that end of the urethra was enough. The penis is slowly disappearing on its own. The male urinary tract starts about halfway "up" the animal goes back almost to the anus and then loops forward back to the penis. The loop gives an excellent opportunity for stones to get trapped. As to the cause, hopefully your vet saved some of the stones for analysis. Cheapest is to send the sample to Dr. Williams (email for details and form to use). Typically Dr. Williams is significantly cheaper than local path labs. In Ives case he made medical history because no one had seen similar stones in anything, which doesn't help us for prevention. We did have a serious heart to heart talk with Ives, asking him to let us know sooner when he is in pain. He promised to try! ;-> Greg Hastings [log in to unmask] Alice Dutton Auburn, WA When one finds himself in a hole of his own making, it is a good time to examine the quality of workmanship. [Posted in FML issue 1435]