Kidney stones are hard, pebble-like pieces that can form in your kidneys when certain minerals and salts in your urine clump together, and they can be very painful. They can be as small as a grain of sand or as large as a marble. They're also quite common, especially in people between the ages of 30 and 60.

Kidney stones can happen when you don’t drink enough fluids. Without enough water, your urine becomes too concentrated, which makes it easier for minerals to clump together and form stones. Other things that can increase the risk include eating a lot of protein but not enough fibre, being overweight, certain medical conditions, or problems with the structure of the kidney, inherited diseases, and certain supplements and medications. All of these can make it more likely for stones to form.

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