| Cover | Nov. 15, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Nov. 15, 2023 |
| Entity Registrant Name | GRI BIO, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-40034 |
| Entity Tax Identification Number | 82-4369909 |
| Entity Address, Address Line One | 2223 Avenida de la Playa |
| Entity Address, Address Line Two | Suite 208 |
| Entity Address, City or Town | La Jolla |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92037 |
| City Area Code | 619 |
| Local Phone Number | 400-1170 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | GRI |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Central Index Key | 0001824293 |
| Amendment Flag | false |
