In the field of medicine, EDTA is approved for use as chelation therapy in acute very high blood calcium levels, mercury and lead poisoning. In the year 2000, the United States approved the use of calcium disodium EDTA or disodium EDTA to promote colour retention for all edible types of cooked, canned legumes. It is to be used in very minute quantities such as 365 parts per million. It has no therapeutic purpose.