Foods high in oxalic acid include: spinach, leek, cabbage, amaranth, bamboo shoots, bitter melon, wild rice, chocolate, coffee and cola. Oxalic acid is a metabolite of living organisms, and when it meets with calcium in the body, it will produce calcium oxalate, thus affecting the absorption of calcium. In addition, for some patients with calcium oxalate stones, try to avoid consuming these high oxalate foods. Generally speaking, healthy people can remove most of the oxalic acid in these high oxalic acid vegetables by blanching them in boiling water in advance. The negative effects of oxalic acid can be greatly minimized with proper preparation. For high oxalates in snack foods like chocolate, coffee and cola, try to consume them in moderation during the day for health reasons.