Several diseases increase the risk of thrombosis in dogs and cats, often with a fatal outcome. Currently there are no definite treatment guidelines for the use of thrombolytic and thromboprofylactic agents in veterinary medicine. None of these drugs are approved for dogs and cats in Sweden. Medicines aimed for humans have been used tentatively. This literature study is an investigation of what is currently known about the effects and safety of these pharmacological agents when used for dogs and cats.