The mechanism of toxicity (in dogs) is specifically relevant. There are multiple studies showing that artificial sweeteners in general are unhealty -- the body recognizes them -- and takes a variety of actions as a result.

Clearly these reactions in some cases may be simply performance related (see: http://www.gssiweb.org/Article/sse-118-carbohydrate-mouth-ri...). Whilst others can be catastrophic (see: xylitol in dogs).