You do not need a prescription to buy any of the products CanadaVet sells.
All the products we sell are over the counter in the country they are shipped from (e.g Australia), and are not for the treatment of serious conditions, and so we consider that they fall within the FDA guidelines which allows US residents to import over the counter pet medicines for personal use (i.e. not for resale).
We serve many tens of thousands of customers in the US and elsewhere who receive their order without issue. The situation in Canada is a little more complicated and Canadian residents should read this important information. Of course, we cannot advise on your own personal circumstances and it is your responsibility to ensure you comply with the guidelines and other relevant laws where you are located.