Arecoline is an alkaloid-type natural product found in betel nuts from the betel palm (Areca catechu). It is an oily liquid that is soluble in water, alcohols, and ether.

In many Asian cultures, the betel nut is chewed to obtain a stimulating effect. Arecoline is the primary active ingredient responsible for the central nervous system affects which are roughly comparable to those of nicotine, which has a similar chemical structure. Arecoline is known to be an agonist of muscarinic M1, M2 and M3 receptors, which is believed to be the primary cause of its parasympathetic effects (such as pupillary constriction, bronchial constriction, etc.).

Owing to its muscarinic and nicotinic agonist properties, arecoline has shown improvement in the learning ability of healthy volunteers. Since one of the hallmarks of Alzheimer's disease is a cognitive decline, arecoline was suggested as a treatment to slow down this process and arecoline administered via i.v. route did indeed show modest verbal and spatial memory improvement in Alzheimer's patients, though due to arecoline's possible carcinogenic properties, it is not the first drug of choice for this degenerative disease. Arecoline has also been used medicinally as an antihelmintic (a drug against parasitic worms).