Before clopidogrel was made available on the market as an antiplatelet medication, aspirin was used in certain cases when a pet needed an anti-clotting medication. Clopidogrel is generally preferred over aspirin since aspirin is associated with significant side effects such as stomach ulcers, severe vomiting, and diarrhea. A study has also suggested that clopidogrel used for cats may be safer and more effective at preventing clot formation than aspirin. Some pets may have severe enough clotting for both medications to be required, but this should only be done at the direction of your veterinarian.   No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.