Hello there. Yes its safe to take one tablet daily after meals and you have to drink lots of water. Not just calcium, but many other things like tomatoes also cause kidney stones but only when the water intake is low as compared to how much needed. So its OK to take it. But keep in mind the hydration part. Take it for a month and then include calcium rich foods in your diet so that you get the calcium from natural sources. Milk and milk products are a great source of calcium. Regards