Twenty to thirty years ago cross-sectional studies reported the intriguing possibility that smoking was actually beneficial in dementia and Alzheimer’s disease . Such findings shone as an encouraging exception in the gloom of the grim and growing catalogue of harm that smoking causes. However, it subsequently became clear that, as with cancers and heart disease, smoking is harmful to cognitive health and is associated with an increase in dementia . But some neurochemists and clinicians detected a signal in the evidence that, whatever harms smoking may cause, nicotine itself might benefit cognition in general and Alzheimer’s disease in particular . Such findings have led to clinical trials investigating this exciting possibility and Dr Newhouse and colleagues have now reported a randomised study in mild cognitive impairment (MCI), a pre-dementia condition.