Rat bioassay for estimating toxicity of plant material from larkspur (Delphinium sp)

A technique was developed for estimating the toxicity for rats of an alcoholic extraction product from larkspur (Delphinium barbeyi Huth). The dried residue from alcohol extraction was reconstituted in buffered saline solution and subcutaneously injected into rats. Toxicity was expressed as miligrams of dry plant per gram of body weight. Samples from D barbeyi collected during prebloom and early flower bud stages of growth produced median lethal doses ranging from 5.0 to 6.7 mg/g of body weight. Difference in toxicity of the extract due to age of rats was not significant.