A Costco spokesman says the company is confident it has complied with legislation governing the sale of pharmaceutical and over-the-counter drugs.
Costco says it's co-operating with an investigation by Ontario's Ministry of Health for its compliance with the legislation.
The health ministry investigation comes after the Ontario College of Pharmacists announced it would hold disciplinary hearings for two Costco pharmacy directors.
The college says there are allegations the two accepted kickbacks for stocking certain brands, which is banned under the Ontario Drug Benefit Act.