Leave the stem/leaves on. Leave the skin on if it is organic. This is the recommendation from a juicing book that I use. One day I prepared carrot/apple and 1/2 beet juices for three of us. My sister drank hers and did not notice a difference. My cousin drank hers and she said she could feel something happening in her stomach and had a bowel movement within the hour - caused by the drink. I got very sick for about 2 hours. I was nauseous, with a fever and running to the bathroom. I of course am the sickest and have been doing detox for awhile. Just to show that it really is an individual reaction.