Consult with your veterinarian if your dog has diarrhea for longer than 24 hours or immediately if it is accompanied by any other signs of illness. (doghealth.com)
I just learned that lots of babies have diarrhea when they're teething. (babycenter.com)
A dirty bottom is common when dogs have diarrhea, long hair, stiffness that prevents cleaning, or are obese. (1800petmeds.com)