AbstractThe levels of S‐adenosylmethionine (SAM) were determined in the livers of male weanling rats fed six different forms of selenium for five weeks. The following forms of selenium were administrated in the diet in logarithmic doses: sodium selenite, sodium selenate, sodium selenide, selenomethionine, selenocystine, and selenium sulfide. An overall increase in hepatic SAM was observed, and all compounds resulted in at least one observation where SAM was significantly elevated (p<0.01). No dose‐response relationship was found to exist, however. A comparison of the relative toxicity of each of the selenicals was based on a dose of 10 ppm dietary selenium for each chemical form. The elevation of SAM resulting from the subchronic administration of selenium may be one mechanism involved in the well‐known chemopreventive effects in experimental models.