Johnson's Diarrhoea Tablets Johnsons Diarrhoea Tablets aid the relief of symptoms of mild diarrhoea caused by minor disorders, unsuitable food, change of diet, etc. Johnsons Diarrhoea Tablets are suitable for cats & dogs, as well as puppies & kittens over 12 weeks of age. Witholding food but NOT WATER for 24 hours from the start of the diarrhoea may also be benefical.