when i first did it i used a small square about 2x2 inches. after i got used to it and the cramping stopped and the colon started getting healthy i use an entire big one mixed with a whole clove of garlic and a chunk of ginger and some spirulina mixed with water or coconut water. everybody is different so go by your own body and your reactions and how you feel. remember you usually feel worse before you feel better. the leaves i buy in my grocery store are usually about 15 inches long and a half inch or less thick and i use the entire thing all the gel. start slow and go from there depending on gut reactions and die off etc. a good video to watch is on you tube. type in jamaican aloe vera or aloe vera health benefits. happy healing.