Kidney Problems 
See also “Kidney Stones”
Congestion, high pitta, or crystal urea in the kidney, as well as kidney stones, can all create tightness and pain in the lower back area. For these problems, Ayurveda suggests the following simple remedies.
First, prepare a mixture of these herbs:
punarnava 1 part
gokshura 1 part
fennel seed 1 part
Take 1 full teaspoon of this mixture 2 or 3 times a day after meals, washing it down with warm water.
Another simple, natural treatment for kidneys is cumin-coriander-fennel tea. Prepare the tea by mixing equal amounts of these herbs, boil in water, and drink 2 or 3 times a day. (Use about ¼ teaspoon of each herb per cup of water.)
For another effective remedy, combine about ½ teaspoon of the Ayurvedic herb musta with ½ teaspoon fennel, steep in a cup of hot water for 10 minutes, strain, and drink. This drink will strengthen the kidneys.