Definitely the acidic juices, especially orange juice. Milk, at times, but not cheese. Anything with grease. I don't drink coffee, but colas will do it, too. But I can drink tea. Tomato products, especially heavily spiced. Another thing I will do when it is acting stupid is go to a very plain diet. I don't like boring diets, but my stomach needs a break every now and then. I just had to experiment over the years on what causes it. Strangely, what bothers me one month may not bother me the next. I don't understand it, but just have to work around it.