The Canadian Food Inspection Agency says the oysters being recalled originated in British Columbia and have harvest dates of Mar. 9, 15, and 19.
The CFIA says they were sold in B.C., Alberta, Saskatchewan, Manitoba, Yukon, and Ontario, and possibly other provinces and territories as well.
They should be thrown out or returned to the place of purchase.
The CFIA says there have been reported illnesses associated with the consumption of the oysters.
It notes that people with norovirus illness usually develop symptoms of diarrhea, vomiting, nausea and stomach cramps within 24 to 48 hours.