Try changing food to vitalin sensitive and combined with chappie tin meat with lots of water. It works for my dog who has not had any issues since.  She was getting this problem three times a week.

Hi,I had a friend visit today,who says her friend has a shih tzu with colitis,and manages it with slippery elm food.I know this is soothing to the stomach,but thats all!Has anyone else had success with this?

I have always found the tiny breeds tend to be quite loose and more likely to have stomach upsets.

I have now, for several years, put a sprinkling of Tree Barks Powder (same thing) on their food.  I do it now as habit.  It has certainly reduced considerably the gippy tums problem.