Yogurt adds probiotics (good bacteria) to the gut and pumpkin adds bulk fiber (food for the good bacteria to eat).
Use only 100% pure canned pumpkin, NOT the spiced pie filling and use no more than 2 tsps, as too much can cause the runs instead of combating the runs.
Pumpkin is really only good in the short term. It begins to lose its effectiveness if used over a period of time. Best to use it only during times of the runs, or during courses of antibiotics instead of all the time.