[[Fail:Nicotine-2D-skeletal.png|thumb|right|250px|Rajah struktur sebatian nikotin]]
[[Fail:Nicotine-2D-skeletal.png|thumb|right|250px|Nikotin]]'''Nikotin''' (atau '''nikotina''') ialah sejenis sebatian organik yang dijumpai secara semulajadi di dalam pokok tembakau (daun tembakau mempunyai kandungan nikotin paling tinggi). Sebanyak 0.6–3.0% daripada berat kering tembakau dianggarkan terdiri daripada nikotin.<ref>{{cite web|url=http://dccps.nci.nih.gov/tcrb/monographs/9/m9_3.PDF|title=Smoking and Tobacco Control Monograph No. 9|last=|first=|date=|website=|format=PDF|archive-url=|archive-date=|dead-url=|accessdate=19 Disember 2012}}</ref> Kandungan nikotin yang berjumlah surih juga ditemui dalam tumbuhan famili ''Solanaceae'' termasuk [[tomato]], [[terung]], [[Kentang|ubi kentang]], dan lada hijau.<ref name="acs">{{cite journal|last1=Siegmund|first1=Barbara|last2=Leitner|first2=Erich|last3=Pfannhauser|first3=Werner|date=1999-07-23|title=Determination of the Nicotine Content of Various Edible Nightshades (Solanaceae) and Their Products and Estimation of the Associated Dietary Nicotine Intake|url=http://pubs.acs.org/cgi-bin/abstract.cgi/jafcau/1999/47/i08/abs/jf990089w.html|journal=J. Agric. Food Chem.|volume=47|issue=8|pages=3113–3120|doi=10.1021/jf990089w|accessdate=2017-04-25}}</ref><ref name="Domino1993" /><ref>{{cite journal|last=Moldoveanu|first=Serban C.|last2=Scott|first2=Wayne A.|last3=Lawson|first3=Darlene M.|date=2016-04-01|title=Nicotine Analysis in Several Non-Tobacco Plant Materials|url=https://www.degruyter.com/dg/viewarticle/j$002fcttr.2016.27.issue-2$002fcttr-2016-0008$002fcttr-2016-0008.xml|journal=Beiträge zur Tabakforschung International/Contributions to Tobacco Research|language=en|volume=27|issue=2|doi=10.1515/cttr-2016-0008|issn=1612-9237|access-date=2017-05-05}}</ref>
Nikotin merupakan racun saraf manjur (''potent nerve poison'') dan digunakan di dalam racun serangga<ref>{{Cite book|title=The chemical components of tobacco and tobacco smoke|last=Rodgman|first=Alan|last2=Perfetti|first2=Thomas A.|publisher=CRC Press|year=2009|isbn=1-4200-7883-6|place=Boca Raton, FL|lccn=2008018913}}{{page needed|date=December 2013}}</ref><ref name="Ujvary">{{Cite book|title=Nicotinoid Insecticides and the Nicotinic Acetylcholine Receptor|last=Ujváry|first=István|publisher=Springer-Verlag|year=1999|editor-last=Yamamoto|editor-first=Izuru|location=Tokyo|pages=29–69|contribution=Nicotine and Other Insecticidal Alkaloids|editor2-last=Casida|editor2-first=John}}</ref> kerana sifatnya yang beracun kepada sebarang haiwan yang berkemungkinan akan memakan tumbuhan yang mengandungi bahan ini.
