Cover - shares	9 Months Ended
	Sep. 30, 2021	Nov. 05, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2021
Current Fiscal Year End Date	--12-31
Entity File Number	000-50099
Entity Registrant Name	GRAPEFRUIT USA, INC.
Entity Central Index Key	0001205181
Entity Tax Identification Number	95-4451059
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	1000 Northwest Street
Entity Address, Address Line Two	Mid-Town Brandy Wine
Entity Address, Address Line Three	Suite 1200-3094
Entity Address, City or Town	Wilmington
Entity Address, State or Province	DE
Entity Address, Postal Zip Code	19801
City Area Code	310
Local Phone Number	575-1175
Title of 12(b) Security	No par value common stock
Trading Symbol	GPFT
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		554,162,744