| Cover | Sep. 21, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | First Wave BioPharma, Inc. |
| Entity Central Index Key | 0001604191 |
| Document Type | 8-K |
| Amendment Flag | false |
| Current Fiscal Year End Date | --12-31 |
| Entity Emerging Growth Company | true |
| Document Period End Date | Sep. 21, 2021 |
| Entity Ex Transition Period | false |
| Entity File Number | 001-37853 |
| Entity Incorporation State Country Code | DE |
| Entity Tax Identification Number | 46-4993860 |
| Entity Address Address Line 1 | 777 Yamato Road |
| Entity Address Address Line 2 | Suite 502 |
| Entity Address City Or Town | Boca Raton |
| Entity Address State Or Province | FL |
| Entity Address Postal Zip Code | 33431 |
| City Area Code | 561 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Local Phone Number | 589-7020 |
| Security 12b Title | Common Stock, par value $0.0001 per share |
| Trading Symbol | FWBI |
| Security Exchange Name | NASDAQ |
