Recuperation from lithium-induced illness: flavor enhancement for rats

Three experimental groups of rats received a 1.0% solution of sodium saccharin 30, 60, and 90 min, respectively, after an ip injection of 15 ml/kg 0.12 M lithium chloride, while a control group received only the saccharin solution. After four such pairings, the groups whose lithium-to-saccharin intervals were 60 and 90 min showed an increased preference for the saccharin solution. The results indicate that repeated pairings of a taste with recovery from illness can produce a "medicinal effect," even in the case when lithium chloride is used as the illness-inducing agent, and that the failure to find this effect in the previous investigations might be due to an insufficient number of LiCl-taste pairings.