Mini schnauzers/mouth foam

Question
I took my 2 mini schnauzers (10 lbs each, 14mo old) out for a walk(not long, not hot)this evening.  The did their business and were kinda just sniffing around.  I didn't notice them eating anything, but all of a sudden they were both foaming at the mouth!  The looked like they had both eaten a bar of soap!

I took them inside, cleaned their faces and the inside of their mouths, gave them some water.  Now they are running around playing with each other like nothing ever happened...What do you make of this?  

My 12yr old daughter says they probably licked a toad...I don't think this is the case because I've seen my dogs trying to play with a frog and they get very excited and jumpy and I would have noticed.  Anyway, would a toad or frog be poisonous to dogs?  Thanks for your time.  

Answer
Lisa -

Your daughter is right - some frogs and toads do have substances that are defense mechanisms to ward off predators.  

Ingestion of some toads can prove deadly. Check with your local veterinarian for the name  and the location of any poisonous toad in your area.  It is wise to know how where these toads can be found in order to avoid them.

Best Regards,

Charlotte Sherrell, DVM