By means of laboratory experiments under controlled conditions, fifty-two native plants were examined with respect to their palatability to the land snail Cepaea nemoralis. Palatability was inferred from the consumption of fresh leaves and from the consumption of filter paper treated with an aqueous leaf extract. C. nemoralis proved to be a convenient laboratory subject and showed consistent food preferences. The experiments using filter paper provided a sensitive test for `chemical' deterrents to feeding. Unpalatable solutes were obtained from a number of species, e.g. Plantago lanceolata, Scabiosa columbaria and Lathyrus pratensis, which previously had not been recognized as unpalatable to herbivores. Only 20% of the species examined were palatable to the snails. Among the palatable species a high proportion were plants associated with disturbed habitats and fertile soils. With the exception of Holcus lanatus, grasses were rejected by Cepaea nemoralis. Leaves with a hard exterior were most unpalatable; this applied even in the case of species, e.g. Festuca ovina, which form the main diet of mammalian herbivores. Under the experimental conditions, leaf hairiness was not an effective barrier to consumption.