
I looked up a post I made in 2008 on this subject:
My bitch in her younger days used to be prone to bouts of diarrhoea, following a severe reaction to an overdose of wormer as a young pup. Eventually, my vet diagnosed an overgrowth of bacteria in the gut, for which she was treated fairly successfully. In her middle years, she suffered a bout of constant vomiting. I then opted for an endoscope test, which showed a very small amount of helicobacter pylori in the stomach. If left untreated, it could have led to an ulcer or a tumour. She was given strong antibiotic, and the bouts of upset stomach have never returned - it's been a few years now.
I don't think the helicobacter could have been there the whole time, but obviously her gut flora were never as they should have been. I used a powdered probiotic, and that helped - it was recommended to me by someone who had used probiotic for horses. I can't remember the brand, but I think it was TDP. Yes, I just looked it up - it was TDP Probiotic by Aviform. I should think the natural yoghurt will do just as well, though. "
To add to this, she did not need to go a 'special' diet. Once the helicobacter pylori had been treated, the problem never returned. I fed her Ardengrange Lamb and Rice for many years after, followed by a fish-based food at the end of her life as the AG recipe had changed. She was a picky youngster growing up following the overdose of wormer (which was an adult dose accidentally prescribed for her at less than four months of age) - that's where her problems began. In later life, she was a greedy guts.