Can I take garlic with an anticoagulant? Thanks.

Ask. the doctor who prescribed the anticoagulant. Garlic thins the blood and (S)he may not want you to use it.
You have not. specified the anticoagulant to which you are referring however there is no reason to believe that garlic in usual doses would have any significant interaction with Vitamin K antagonists nor Factor ten A inhibitors nor thrombin inhibitors either. Check with your health care provider to address your specific situation.