from Healthwyze.com . . . . 

Eliminating Kidney Stones
Some people have managed to pass kidney stones by eating large amounts of watermelon. However, our research has concluded that the popular lemon juice and oil combination is the most effective method. Lemon juice breaks down the stones, while oil provides lubrication to allow the stones to pass.

To perform a lemon and olive oil cleanse, blend 5 ounces of lemon juice with 5 ounces of olive oil. Extra-virgin olive oil is best because it is the healthiest, and it has a thicker consistency than most other food oils. People may wish to add a small amount of honey to improve the taste. Drink the solution as quickly as possible. Do this once in the morning, and once in the late afternoon. Continue this for several days, or until the stone passes. Drink plenty of water throughout this process, including extra lemon juice if possible.

Also, know the difference between gallstones and kidney stones.

 I tried this because I was experiencing screaming pain in my waist, lower back, and in my core.  After one day of exclusive cleanse--no food, except for maybe a cup of coffee--I was unbelievably flexible and mobile again.  In the morning, I couldn't tie my shoes.  By night I was doing leg lifts.  I could not believe how effective it was.   

For a list of added benefits from lemons, check this out.  

Here are a few more benefits of lemon that you might find useful.  It is an impressive fruit.