One of my Patterdale terriers just had diarrhea for the past week. It was starting to have some bright blood and mucous laced with it. We hoped it was going to pass, but had to take her to the vet. I was very nervous, because I had researched on the Internet and thought the worst. It turned out she must have eaten something really nasty at some point and it had upset the bacteria in her digestive tract. She had a very high level of a certain bacteria. The vet said yogurt would have helped. I had read something about that, but was afraid to try something on my own and lose my pup over it. The vet put her on several medicines and some special diet canned food. With two other puppies at home it was nice to know she wasn't contagious. Now we know something to try next time. It was worth the money to know she will be alright and not pass anything to the other dogs.