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No Evidence for Benefit

by Elmer M. Cranton, M.D.

EDTA rectal suppositories are being promoted as a substitute for intravenous chelation. Research showing that EDTA is very poorly absorbed by rectum, less than 7%. EDTA retained in the rectum can damage the mucosal lining.

EDTA suppositories are being deceptively marketed as past of a scheme involving alleged nanobacteria.

Published research shows that the colon and rectum absorb very little EDTA.(1) 51Cr-radioactive isotope labeled EDTA is used as a tracer to study abnormal intestinal permeability precisely because it is not well absorbed. When EDTA enters the circulation it is rapidly excreted in the urine. In a published study the authors determined that 85% of an intravenous dose of EDTA was recovered in the urine after 6 hours.(1) They also reported that when a saline solution of EDTA was administered by enema, only “. . . 7% of the 51Cr-EDTA instilled into the colon can be recovered in urine over the next 6 hours.”(1) These results show that very little EDTA can be absorbed when distributed throughout the colon by enema. Even less would be absorbed if administered by suppository and limited to the rectum.

Another research study was been deceptively cited by marketers of EDTA suppositories by erroneously stating that it provides evidence for safety.(2) The opposite is true. The cited study showed a high incidence of damage to the lining of the colon and rectum from direct application of EDTA. A 250-ml enema containing a dilute 0.5% solution of EDTA was administered to a group of dogs. Half of those dogs were found to suffer mucosal hemorrhages of the colon and rectum two hours after instillation of EDTA. Rectal suppositories release all of their EDTA in a small area, producing a much higher local concentration for a prolonged period of time, while an enema dilutes the EDTA throughout the entire colon. Even with a lower concentration, half the dogs suffered mucosal hemorrhages.(1)

This same type of damage to the rectum would be expected after taking EDTA by mouth, since very little oral EDTA is absorbed. Oral EDTA thus ends up in the rectum, much like a suppository.

Rectal cancer is not uncommon. An important defense against cancer is superoxide dismutase (SOD). SOD is a metallo-enzyme that must have zinc, copper, and manganese to function. EDTA has a very high affinity for all three of those metals. If EDTA is retained at high concentrations in the rectum, it will bind tightly to those essential metals and remove them from the mucosal lining of the rectum, inactivating intracellular SOD and other vital metalloenzymes. Latency for rectal cancer can take years for transformation from benign to malignant cells. It would require quite a long study to prove that repeated use of rectal EDTA is safe.


1. Elia M, Behens C, Northrop C, Wraight P, Neale G: Evaluation of mannitol, lactulose and 51Cr-labeled ethylenediaminetetra-acetate as markers of intestinal permeability in man. Clinical Science 1987;Aug 73(2):197-204.

2. Rabau MY, Baratz M, Rozen P: Na2 ethylenediaminetetraacetic acid retention enema in dogs: Biochemical and histological response. Gen Pharmacol 1991;22(2):329-30.

Copyright © 2012 Elmer M. Cranton, M.D., all rights reserved

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