(-)-cotinine is an N-alkylpyrrolidine that consists of N-methylpyrrolidinone bearing a pyridin-3-yl substituent at position C-5 (the 5S-enantiomer). It is an alkaloid commonly found in Nicotiana tabacum. It has a role as a biomarker, an antidepressant, a plant metabolite and a human xenobiotic metabolite. It is a N-alkylpyrrolidine, a member of pyridines, a pyrrolidine alkaloid and a member of pyrrolidin-2-ones.