Emergency dog muzzle (halfway down the article - drawings):  
http://www.petfocused.com/articles/pet-health/pet-first-aid/common-pet-injuries.phpThere is an Animal Poison Control Center (24 hrs) at (888) 426-4435.  You'll need a credit card for the $65 fee.
The human Poison Control Center (24 hrs) is 1-800-222-1222 and is free.  I've had to call them three times, and they were perfectly helpful each time.  TELL THEM IT IS A PET!  Don't say it's a kid or anything, they're okay with pets.  Have approximate weight and the info on whatever they got into right at hand.
Sue