I do a lot nutritional and chemical nutritional work. So I know quite a bit about how to fix most health issues. Yes the lemon does work but depends on the type of kidney stone. Two types of stone, comes down to how acidic or alkaline your urine is. In your latest urinalysis it will say urine PH and SG or specific gravity. That is a big indicator of stone formation. Low pH is bad, too high is bad too. I say best between 6.2 and 6.5 ph, anything above 7 is not good. Every .1 pH difference is double the acidity. So the difference between Ph7 and Ph6 is 10x, PH7 to PH5 is 100 times. As amazing as it sounds lemons even though are acidic create a alkaline environment in the body after being digested. If you want to know more about this kind of effect look up PRAL food guidelines. PRAL is potential renal acid load on the kidneys. Let's you know which foods will make you more acidic and which more alkaline.