There are two types:

  1. Normal lemon

  2. Lime

Basically, these fruits have a lot of citric acids.

Calcium which is in the salt is the reason to make stones in our kidneys.

In San Diego City (America), scientists found that lemon or sweet lime juice reduces the calcium level and prevent creating stones in our kidneys.

So creating stone can be completely stopped by reducing the salt level in our daily food and consuming lemon or lime juice more.