Not for gastric ulcers but have used it as a probiotic in my mare that had very loose droppings - had tried lots of others and the Protexin did the trick really quite quickly and she didn't have the problem again.
not for that - my farrier recommended it to me to aid my horse going barefoot - helps with toxins etc and have also found it has helped with loose droppings when feeding rich haylage. I would recommend it though - I could see how it would aid ulcers.
i used it on my mare when she was scouring very badly after a lot of stress with suspected but never confirmed ulcers, symptons been there for 2 weeks, after 1 weeks use symptoms almost disappeared, now i feed it as part of her daily diet, wouldnt be without it.