For dogs yes, but only if your dog is bright, has an appetite, and is not vomiting, nor showing any signs of abdominal pain.
The dose for dogs is 1ml per 4kg of body weight (in English that is about 1 tsp. per 40 lbs.). It should be given three or four times a day. Pepto-Bismol® is an ancillary therapy to the usual strategies for managing diarrhea which are to: allow your dog to drink as much water as they want and withhold food until 24hours have passed since the last bout of diarrhea. The active compound in Pepto-Bismol® is bismuth subsalicylate. This compound is cleaved in the small intestine into bismuth and salicylate. Salicylate is also the active compound of Aspirin®. Cats cannot clear salicylate from the body like dogs and people can. Therefore inappropriate dosing of either drug can quickly become toxic to your cat. Do not use Pepto-Bismol® or Aspirin® for your cat unless directed by your veterinarian. If diarrhea persists for five days or worsens while on Pepto-Bismol®, discontinue the medication and schedule an appointment with your veterinarian.