After two weeks habituation to capsaicinized food, rats prefer this to plain food.

In a first series of experiments rats were accustomed for two weeks to eat chow with capsaicin (250 micrograms: 1 g of food). After this habituation period, when free to choose, 3 rats out of 4 preferred eating the piquant chow. In a second series of experiments the rats had access to a choice of chows without any habituation period. In this series, the choice between piquant and nonpiquant chow showed that 4 rats out of 5 preferred to eat the chow without capsaicin. The present experiment shows that the piquant chow eaten by rats produced a fall in rectal temperature 48 h later. The present experiment provides some evidence that rats accustomed to eat piquant food manifested, when free to choose, a preference for an innately unpalatable piquant chow.