Abstract
Psychosocial factors can influence immune functions: the brain intermediates between the outside world and the inside of the body. The functional interaction between the central nervous system and the immune system is effected by 2 different pathways: the nervous “wiring system” innervating lymphoid tissues and the “soluble connection” via the neuroendocrine system. The paper reviews data from the literature regarding changes in susceptibility to infections due to stressful conditions. Emphasis is given to information regarding infection of the oral cavity and the upper respiratory tract.