Apparently so. But equally, it's supposed to be quite an effective
laxative, which might be why dogs eat it. Your takes your chances...!
Looking on another site, I see the some people swear it prevents
laminitis
in horses.

I have heard this one too but never tried it. Horses seek out all sorts of
stuff to eat, they know things that we don't. Best thing this time of the
year is Cow parsley, very yummy

kate