Cytisine is an organic heterotricyclic compound that is the toxic principle in Laburnum seeds and is found in many members of the Fabaceae (legume, pea or bean) family. An acetylcholine agonist, it is widely used throughout Eastern Europe as an aid to giving up smoking. It has a role as a phytotoxin, a nicotinic acetylcholine receptor agonist and a plant metabolite. It is an alkaloid, a lactam, an organic heterotricyclic compound, a bridged compound and a secondary amino compound. Cytisine is a nicotinic acetylcholine receptor agonist, has been widely used for central nervous system (CNS) diseases treatment. It is a partial agonist at alpha4/beta2 nAChRs, and a full agonist at alpha3/beta4 and alpha7 nAChRs, has antidepressant-like properties in several rodent models of antidepressant efficacy.

Norgalanthamine is a benzazepine.