Ingredients:

1 head romaine lettuce or any green leafy vegetable
3/4 cup blueberries, fresh or frozen
1 apple, roughly chopped
1/4 lemon or lime
2 cups water

Put all ingredients in a blender and blend until smooth. Enjoy!

Read about the benefits of green smothies here:

5 Reasons to Reach for a Green Smoothie to Fast Track Your Health