The title of this study may be misleading: “Antioxidant and anticholinergic effects of rosemary extract: a double-blind randomized controlled trial”.
In this small-scale study, 1000 mg per day of rosemary powder was found to increase total antioxidant activity and decrease acetylcholinesterase (AChE) activity. Decreased AChE activity means increased activity in cholinergic neurons; thus rosemary does not have an anticholinergic effect but a cholinergic one. The dysfunction and loss of basal forebrain cholinergic neurons and their cortical projections are among the earliest pathological events in Alzheimer’s disease (Wikipedia). Indeed the authors allude to the potential use of rosemary in patients with Alzheimer’s disease.