A syndrome in which a person reports multiple symptoms that he or she believes are due to low-level chemical exposure and that interfere with daily life and work. People with this condition often report symptoms after they have been exposed to an environmental chemical, such as a pesticide or chemical used in a building remodeling. The exposure level is typically low enough that it should not cause symptoms, but after a suspected exposure, the person may have multiple symptoms in response to previously tolerated low-level exposures. Symptoms include fatigue, difficulty concentrating, a depressed mood, memory loss, weakness, taste disturbance, dizziness, headaches, and heat intolerance. In severe cases, people with MCS will alter their behavior to avoid what they presumed brought on their symptoms.