Veterans of the 1991 Gulf War reported various physical and mental symptoms. They sometimes reported symptoms that were poorly defined or were not limited to any 1 organ in the body. These included fatigue, joint and muscle pains, night sweats, rashes, headaches, diarrhea, and problems with thinking clearly or with memory. Few studies examined the types and frequency of medical conditions among these veterans many years after the completion of the war. In addition, no large studies compared the frequencies of persistent or chronic medical conditions among veterans who were and were not deployed during the war.