OBJECTIVES: Amaryllidaceae alkaloids are well known for their wide range of pharmacological activities. Galanthamine, an Amaryllidaceae alkaloid, is an effective, selective, reversible, and competitive cholinesterase inhibitor marketed under different commercial names in several countries for the treatment of Alzheimer's disease. The aim of this work was to study the alkaloid profiles of the aerial parts and bulbs of both flowering and fruiting periods of Galanthus fosteri Baker (Amaryllidaceae), as well as analyzing their inhibitory activities on both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) for the first time. MATERIALS AND METHODS: The alkaloid profiles of the four samples were determined by means of gas chromatography-mass spectrometry, and AChE and BuChE inhibition assays were performed by the modified Ellman method. RESULTS: Totally, 22 compounds with mass spectral characteristics of Amaryllidaceae alkaloids were detected in the extracts. Significant AChE and BuChE inhibitory activities were observed in the tested samples (IC(50) between 0.189 and 91.23 mug/mL). CONCLUSION: This study shows that G. fosteri, collected from Akdag, Amasya (Turkey), is a potential source of diverse chemical structures of Amaryllidaceae alkaloids with cholinesterase inhibitory properties. CI - (c)Copyright 2020 Turk J Pharm Sci, Published by Galenos Publishing House.