The U.S. Department of Defense has banned the sale of aspirin in the military version of 7-11s (the Base or Post Exchanges) in combat zones. The reason is simple; aspirin "thins the blood" (inhibits clotting). The medical community has known this for generations, and sometimes uses aspirin for treating patients in need of less clotting. But American soldiers are recruited for, among other things, sound health. A soldiers biggest risk, especially in a combat zone, is getting wounded, and then you need rapid clotting to help halt the bleeding. Thus the ban on aspirin. There are other drugs available that can do the same pain relieving job as aspirin, but do not inhibit clotting. Troops are also told not to bring aspirin with them when they are transferred to a combat zone. This is a policy that will save a few lives, and lead to less serious injuries. Blood loss, and its complications, are a major cause of combat deaths and more severe injuries.