Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Mar. 09, 2021	Jun. 30, 2020
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity File Number	001-36338
Entity Registrant Name	22nd Century Group, Inc.
Entity Central Index Key	0001347858
Current Fiscal Year End Date	--12-31
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	98-0468420
Entity Address, Address Line One	8560 Main Street
Entity Address, Address Line Two	Suite 4
Entity Address, City or Town	Williamsville
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	14221
City Area Code	716
Local Phone Number	270-1523
Title of 12(b) Security	Common Stock, $0.00001 par value
Security Exchange Name	NYSEAMER
Trading Symbol	XXII
Entity Current Reporting Status	Yes
ICFR Auditor Attestation Flag	false
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 106
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		149,615,010