Horse "foaming at the mouth" What does that mean when you see it?

[Indian Charlie]

Originally Posted by CharlieR

Can someone with horse knowledge / training experience tell me why some horses will "foam" at the mouth?
Charlie

It usually means the horse has found out that PG1985 placed a bet on it. It's a sign of nerves.

Originally Posted by CharlieR

Should you be concerned about a horse's condition that shows this? And if you should be concerned would only be if they were running that day or how about if running in a couple of days from now?
Charlie

Yes. Be very concerned.