###Human: Can Aspirin reduce the risk of stroke during flight travel in a patient with high RBC, Hb, hematocrit? ###Assistant: Hi. I agree with you. There is a risk of leg vein thrombosis in deep veins of legs due to prolong sitting. Aspirin do help according to some studies, might be not as beneficial as full anticoagulants like Heparin, etc., but take Aspirin 325 mg (not 75 or 81 mg) one hour before flight with meal. Walk during flight in aisles frequently. Keep yourself hydrated. I believe you will be fine.