Resveratrol supplements are marketed on the premise they enhance cognitive function. We explored effects of resveratrol supplementation on cognitive function, in the absence of pathology, by assessing effects of resveratrol on the performance of young, healthy, recently gonadectomised dogs in an eight-arm radial maze. Effects of gonadectomy on cognition were also assessed. Performances of untreated intact dogs, resveratrol-treated gonadectomised dogs (60mg/day of resveratrol orally) and placebo-treated gonadectomised dogs were compared in three phases. Dogs received the placebo or resveratrol for two to four weeks before testing began. In phase one, untreated intact (n = 16), resveratrol-treated go-nadectomised (n = 6) and placebo-treated gonadectomised dogs (n = 5) were allowed to choose all maze arms they en-tered. In phase two, untreated intact (n = 15), resveratrol-treated gonadectomised (n = 6) and placebo-treated gonadec-tomised dogs (n = 5) entered four predetermined arms and then made four free choices from all eight arms. In phase three, a subset of dogs previously tested as untreated intact dogs in phases one and two were tested. In phase three, placebo-treated gonadectomised (n = 6) and resveratrol-treated gonadectomised dogs (n = 6) entered seven predetermined arms and then had free choice between a previously opened arm and the unopened arm. Performance in the maze did not differ significantly between gonadectomised dogs receiving the placebo and gonadectomised dogs receiving resveratrol or be-tween untreated intact dogs and gonadectomised dogs receiving the placebo. We conclude that resveratrol treatment does not improve (and gonadectomy does not impair) the aspects of cognitive function that were tested by the radial arm maze trials in young, healthy dogs receiving extensive handling and environmental/behavioural enrichment.