I was poking around on some of the CFS lists on yahoo and there is a list for people doing this vitamin protocol by Dr. Yasko. I checked out the stuff and they talk about tendency to high ammonia and taking Yucca and Activated Charcoal to help deal with it. Its more complicated than that and has to do with some genetics that pre-dispose people to over produce ammonia in some cases, but you might want to look into it. I have never taken either... But your post made me think of what I read over there. The yahoo group is CFS_Yasko.