I used to get this REALLY strong before I started doing HST.... I still do get it sometimes, but it's no where what it used to be... Like you, I've been concerned about it too. I asked my doctor about it, and he said it maybe caused by a break down of muscle since ammonia is a by product. Another opinion came from Kate. I can't remember what she said, but if you search the archives, I'm sure you'll find my old question w/her answer...