I am not aware of any home remedy involving the use of yogurt and vinegar together in order to treat a peptic ulcer. In fact, vinegar is acidic, and so I don’t see how it can help. If anything, it will make the problem worse. Treatment for ulcers often involves the use of antacids on the contrary. I would therefore advise you against using any such home remedy for your peptic ulcer, no matter where you got it from. Yogurt could be helpful, but by itself it will not really solve the problem. It does tend to soothe the stomach though, and is beneficial in many other ways as well, so you can eat some yogurt daily, or at least whenever you feel the abdominal pain, bloating, and nausea that the ulcer causes.
I am not sure exactly what you meant by “stomach upset” — if you were referring to the stuffed, puffy feeling, some amount of pain, and nausea, then it is quite certainly due to a peptic ulcer. However, if you were referring to diarrhea, then you should ask your doctor whether there could be some other problem, as a peptic ulcer should not usually cause diarrhea.
If you do indeed have only a peptic ulcer, I hope that you are being treated for it. Peptic ulcers can become quite serious if they are untreated for a long time, and can even result in perforation of the stomach wall, which is an emergency and requires surgery. Even if you are not on medication, you should be careful what you eat — oily, spicy food is to be avoided as far as possible, as is alcohol and caffeine. In addition, you should try to have a regular schedule for eating and sleeping. Stress of course aggravates ulcers, so you should try to avoid it in whatever way you can.
answered by G M