Is pineapple juice safe with barrett's. although it is acidic it is supposed to become alkaline in the stomach.it helps me with regular bowel movement?

You're fine: If it doesn't make you uncomfortable. I suspect you're reading too much folklore about "acid" and "alkaline" foods. There's very little science here. Pineapple actually contains a few proteases that may enhance digestion; if you find it helpful, I'm glad. Often just a few extra glasses of water daily can keep things regular as well. Best wishes.