It was recommended to me on here. It is a herbal remedy (get it from a health shop). It coats the lining of the gut and soothes it if it is irritated.
I mix it into some probiotic yoghurt and stuff his kong with it or you can just mix it with water and put it in his bowl. Just 1 teaspoon mixed to a paste a couple of times a day.
It took a couple of weeks in total. I had him on the rice and chicken for a couple of days originally but it came back as soon as i took him off it so i had to have another go at it plus the slippery elm powder and yoghurt. Awww poor Oscar hope he feels better soon.