When buying pet medicine online, it is very important to make sure you choose a regular and reliable online pharmacy or pet professional website to buy.

Here are some suggestions:

1. Choose a well-known pet medicine brand or the official website of a pharmaceutical company, such as Petco, PetSmart, etc. in the United States.

2. Buy medicines under the prescription of a pet doctor or veterinarian. Some online pharmacies require a veterinary prescription to buy specific medicines, which can ensure the legality and safety of the medicines.

3. Check the qualifications and certification information of the online pharmacy. Make sure the pharmacy has the relevant licenses and legal operating qualifications.

4. Read the reviews and feedback of other users to understand the credibility and reputation of the online pharmacy.

5. Pay attention to medicines that are too low or too high in price. Too low prices may mean that the quality of the medicine is unreliable, while too high prices may be unreasonable.

6. Consult a veterinarian or pet doctor for advice and opinions before buying.

In short, when purchasing pet medicines, be vigilant and choose reliable channels to ensure the health and safety of your pet.