My dog gets diarrhea every time he takes antibiotics (which is pretty often since he has flea bite dermatitis and ends up with a skin infection several times every year from scratching). This clears it up within a day or two, whereas it normally takes a week or more to clean on its own.
I was having to medicate my dogs with Metronidazole, twice a day until I found a holistic vet who recommended this paste. I gave it to them after their first loose stool, and it worked great! No more drugs. I HIGHLY recommend this. It's been a Godsend.