| Cover | Aug. 20, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 20, 2021 |
| Entity File Number | 000-55809 |
| Entity Registrant Name | CANNASSIST INTERNATIONAL CORP. |
| Entity Central Index Key | 0001709542 |
| Entity Tax Identification Number | 82-1873116 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 855 South Mission Avenue |
| Entity Address, Address Line Two | Suite #K400 |
| Entity Address, City or Town | Fallbrook |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92028 |
| City Area Code | 888 |
| Local Phone Number | 991-2196 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | true |
