I wrote: >Some ferrets have trouble with just cystine, others have trouble with >what is termed the "COLA" group" SIGH. We don't know at this point whether ferrets just have trouble with cystine or with the other amino acids in that grouping. I MEANT to write MAMMALS instead of "ferrets". BTW, many people don't think of urinary blockage with constipation but it's not unusual for that to be an early sign or the first sign. Oh, and if you go to the crit. refs in http://www.ferretcongress.org you will be able to link to information on surgery to by-pass the penis when a male's urethra is plugged. Our vet had been told that doing repeated cystos would not work but they were needed to save him until we could get his penis by-passed. Luckily for Hilbert the cystos DID dislodge the small material which blocked him and gave his urethra time to lose its inflammation so he never needed to be rerouted. So, sometimes what people say won't work really will. I later learned from a friend who is a pediatric urologist that the same technique is sometimes used for humans. (A cysto is draining the bladder using a needle. I have also been told of a vet who used a catheter for drainage until the problem resolved -- also avoiding penile by-pass sugery.) Hope that all of this helps. [Posted in FML issue 4755]