Kimpul tubers have anti-nutritional substances in the form of calcium oxalate (CaC2O4) which when consumed will cause itching sensations in the skin, mouth, throat and digestive tract. Calcium oxalate content in kimpul tubers is 1,740 mg / 100 g. The safe limit for consuming oxalate for adults is 0.60-1.25 g per day for 6 consecutive weeks. In this research, a combination of physical and chemical methods will be carried out with taro varieties, namely Umbi Kimpul (Aceh Besar). Physical treatment (boiling and steaming) and followed by immersion treatment with chemicals (6% sodium bicarbonate, 20% acetic acid and 10% sodium chloride) are thought to affect the decrease in calcium oxalate in taro. The lowest oxalate content of kimpul tuber flour was obtained, namely 13.62 mg / 100 g of the material from the boiling treatment by soaking in 20% CH3COOH. While the steaming treatment with the lowest levels of calcium oxalate in kimpul tuber flour, namely 22.28 mg / 100 g after soaking in 6% NaHCO3. The two values obtained from the test results were lower than the calcium oxalate content of fresh kimpul tubers, which was 42.35 mg / 100 g.