The efficacy of activated carbon as an oral adsorbent in removing paraquat and diquat from purified water and physiological saline solution at different temperatures was investigated for the primary treatment of acute poisoning. The amounts of paraquat and diquat adsorbed onto activated carbon were large in low temperature condition. The adsorption mode of paraquat and diquat onto activated carbon was mainly physical adsorption. It was recognized that the high adsorption ratio of paraquat and diquat onto activated carbon was obtained by the administration of low temperature suspended solution which was a mixture of activated carbon and gastrointestinal lavage detergent.