The main issue as I see it with garlic is that the sensitivity to it, varies cat by cat. Some cats *will* develop Heinz Body Anemia and even go on to die, from a minimal exposure, others seem to be fine.
Here is the *most* recent and best article on the topic imho:Click here and scroll to August 2005 Article on Allium Species Poisoning in Dogs and Cats
The article is a pdf file, so you need to have Adobe Acrobat's free reader installed on your system.
The clear undeniable fact is that garlic is in the same family as onions, which are known to be toxic to cats. However, the amount of garlic necessary to cause a problem can vary, and folks, imo, hold to the belief that there are health benefits to cats similar to the benefits to humans.
Points of view that I disagree with - it depends on if fresh or dried, 'special' preparations or varities are okay, minimal amounts won't hurt.
To me, it is a choice, play russian roulette and use it, or don't.
The one good thing I have read...if the decision to cease using garlic is done soon enough for the particular cat reacting to it, the damage may be reversible - I imagine it depends on how much damage (how severe the anemia and other overall health aspects of the cat) has already been done.
There are *fine* companies continuing to use garlic, my one request of them is to please provide foods/supplements with a garlic free option for those of us who do not wish to feed it, and especially those of us with health compromised cats such as my cats with CRF (chronic kidney failure - who are already more prone to a different kind of anemia).
Okay..end of my mini-lecture