The calcium chelate of ethylenediamine tetracetic acid (CaEDTA) was used to protect animals against a toxic culture filtrate of Clostridium perfringens and infection with the organism. CaEDTA given systemically protected mice against 2 MLD of toxin, and guinea pigs which had been given a lethal injection of the organisms. CaEDTA and EDTA also protected the animals when small amounts were injected with the organisms. CaEDTA is not bactericidal or bacteriostatic for these organisms and protects against infection by inhibiting the toxins. This inhibition may be due to the removal of free metallic ions in the body by the cheating agent. The possible use of chelating agents as an adjunct to other chemotheraperutic agents is discussed.