Abstract

It is well documented that various selenium compounds are highly toxic. However, it should be pointed out that there are also certain ionic forms of selenium that are not as toxic when taken orally. One such compound is the water-insoluble selenium sulfide (SeS ₂). Studies were conducted, therefore, to present the following data to support the safety of selenium sulfide and the selenium sulfide-containing shampoos: (1) selenium sulfide (SeS ₂) should not be classified in the same toxicity category as the highly toxic sodium selenite, since SeS ₂ is 20 times less toxic; (2) comparative oral LD50 values in rats of SeS ₂ and active components from other leading antidandruff shampoos indicate that SeS ₂ should be classified in the same toxicity category as these other active ingredients. (3) the oral LD50 values for 1% and 2.5% SeS ₂ shampoos are about 10 times the emetic doses, thus suggesting that a toxic amount of shampoo could not be ingested without emesis occurring; and (4) oral dosing of a 1% SeS ₂ formulation to dogs indicates essentially no absorption as indicated by the lack of an increased selenium blood level.