The only thing I've heard yogart is good for is yeast infections
From what I have read, there is a big debate on whether good bateria can survive stomach acid. Some companies sell good bacteria in powder form which you are supposed to make into a drink. These companies claim that they survive stomach acid and that the powder doesn't need refrigeration. Some articles I have read say to ignore these claims and suggest the capsules. I have also read that the bacteria can be injured in the capsulation process.
I don't know what to believe so I am trying all of them. Whether you can rely on yoghurt alone I would guess it would depend on how badly damaged your digestive tract is. I was on tons of antibiotics and despite eating yoghurt my digestive problems didn't get better. However, after taking probiotics (pill and powder form), my digestion got notably better within a few days.