Acute toxicity testing of erythrosine and sodium fluorescein in mice and rats

Erythrosine and sodium fluorescein, two colors used as a dental plaque disclosing agents, have similar chemical structures differing only in that erythrosine has four iodine atoms in the molecule while sodium fluorescein has no iodine. A comparative toxicological profile was made on both compounds employing oral dose ranges and acute oral toxicity tests in mice and rats. The results show erythrosine to be approximately twice as toxic as sodium fluorescein with LD50 values of 2558 +/- 1.35 mg/kg in mice and 2891 +/- 1.02 mg/kg in rats for erythrosine and 4738 +/- 1.23 mg/kg in mice and 6721 +/- 1.26 mg/kg in rats for sodium fluorescein. The major toxic manifestations of both compounds were those indicative of central nervous system depression.