http://www.smartgroups.com/message/readmessage.cfm? gid=1423922&messageid=8097&startid=8098 The simple answer is no! High protein diets will not cause kidney failure. If there is kidney failure then you want a slightly lower protein level in the food. The lower protein level will help control the clinical signs (vomiting and nausea) and may help extend their lifespan. Totally Ferret and Marshall's both have a "senior diet" with a slightly lower protein level than their regular version. Hope that clears things up, Jerry Murray, DVM [Posted in FML issue 4440]