Oystercal 500mg is a calcium supplement derived from natural oyster shells. Each tablet contains 500mg of calcium, providing a natural source of this essential mineral. The product comes in a package of 20 tablets. This medication is a calcium supplement used to prevent or treat calcium deficiency. The calcium in this product comes from oyster shells, making it a natural source of this important mineral that helps maintain strong bones and supports various bodily functions. Always take this supplement as directed by your healthcare provider.