. . . I don't think I've ever seen a thread derail into something more sane than the original topic, but I'll be damned if that didn't happen here.
Anyway, I seem to remember a book in which Ax mentions eating a snail by accident, but I can't remember which one. Maybe I just made it up in my head, I dunno. Point is, does anyone remember if he said anything about the shell? Because that might give some insight into the lovely topic of Andalite vomit.
That sounds vaguely familiar... honestly I just imagine an Andalite hoof to just "drop" anything that gets in that shouldn't. Sort of like putting something in your mouth, not liking it, and allowing it to just drop out of your mouth... though that's more of a "spitting out" than "throwing up," hmm.
I do remember Ax saying something about eating a snail. I want to say it was in #18? Maybe #8. It was one of his earlier books, anyway.
In that same book, I also remember him commenting on accidentally eating worms, too.
Which kinda goes to show what I was talking about in my first post in this topic (before it derailed into 'sanity,' BOOO), that Andalites, being a species that has so little control over what they eat, are never grossed out or sickened by just about anything, at all, ever. Any reasonable species would have been like "Oh my god I accidentally consumed slimy-alien-invertebrate-snakes get them out of me blechh!" Instead, Ax's reaction was to casually comment that "too much protein tends to keep me awake at night," and then mention a snail he ate once.
For goodness sake, I grew up on this planet, knowing what worms are, and I even eat meat on a regular basis, and the idea of eating worms STILL grosses me out way more than it does Ax.
Point being, that, while Andalites can probably vomit, it is most likely an extremely rare occurrence. Hence why, in #12, Ax says that they don't even really have a word for it.