I also tried Aloe Vera juice several times with very unsuccessful results. I used several brands including the one from Herba Life. After drinking the Aloe juice I always experienced irritation in the lower part of my stomach and in my intestine.
My research has conducted me to think that Aloe juice might not be convenient for IBS sufferers but some of the aloe components are very fundamental in healing IBS, for example Glucomannans and other glyconutrients in it.