Note 15 - Fair Value Disclosures - Fair Value of Financial Instruments (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Reported Value Measurement [Member]
Cash and cash equivalents	$ 10,840	$ 1,908
Other receivables	24,629	113,999
Note receivable – CEN Biotech Ukraine, LLC – related party	44,859	44,859
Loans payable	785,618	527,379
Loans payable – related parties	1,314,395	1,363,354
Patent acquisition liability	302,000	1,380,000
Convertible notes payable	2,139,390	6,730,448
Convertible notes payable – related parties	2,419,983	2,558,681
Reported Value Measurement [Member] | CEN Biotech Ukraine [Member]
Advances to Subsidiary	1,299,328	1,179,328
Reported Value Measurement [Member] | Emergence Global [Member]
Advances to Subsidiary		17,901
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	10,840	1,908
Other receivables	24,629	113,999
Note receivable – CEN Biotech Ukraine, LLC – related party	44,859	44,859
Loans payable	785,618	527,379
Loans payable – related parties	0	0
Patent acquisition liability	302,000	1,380,000
Convertible notes payable	3,328,714	7,766,663
Convertible notes payable – related parties	0	0
Estimate of Fair Value Measurement [Member] | CEN Biotech Ukraine [Member]
Advances to Subsidiary	1,299,328	1,179,328
Estimate of Fair Value Measurement [Member] | Emergence Global [Member]
Advances to Subsidiary		17,901
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	0	0
Other receivables	0	0
Note receivable – CEN Biotech Ukraine, LLC – related party	0	0
Loans payable	0	0
Loans payable – related parties	0	0
Patent acquisition liability	302,000	0
Convertible notes payable	0	0
Convertible notes payable – related parties	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | CEN Biotech Ukraine [Member]
Advances to Subsidiary	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Emergence Global [Member]
Advances to Subsidiary		0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	10,840	1,908
Other receivables	0	0
Note receivable – CEN Biotech Ukraine, LLC – related party	0	0
Loans payable	0	0
Loans payable – related parties	0	0
Patent acquisition liability	0	0
Convertible notes payable	0	0
Convertible notes payable – related parties	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | CEN Biotech Ukraine [Member]
Advances to Subsidiary	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Emergence Global [Member]
Advances to Subsidiary		0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Other receivables	24,629	113,999
Note receivable – CEN Biotech Ukraine, LLC – related party	44,859	44,859
Loans payable	785,618	527,379
Loans payable – related parties	0	0
Patent acquisition liability	0	1,380,000
Convertible notes payable	3,328,714	7,766,663
Convertible notes payable – related parties	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | CEN Biotech Ukraine [Member]
Advances to Subsidiary	$ 1,299,328	1,179,328
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Emergence Global [Member]
Advances to Subsidiary		$ 17,901