The physiological variations of fibrinolytic activity (FA) in saliva w
ere investigated in a population of 149 healthy volunteers including 1
2 pregnant women. An increase in FA could be observed with increasing
age. Marked variations were observed during daytime with a peak value
early in the morning. Higher FA values were observed in males as compa
red with females in the 20-39 yr age group. A clear decrease in FA was
observed during pregnancy. A significant correlation existed between
FA and sus pended epithelial cell concentration, which seemed responsi
ble for most of the physiological FA variations. It was concluded that
age, sex, pregnancy, and the time of the day are important for saliva
ry FA and should be taken into account in any study on salivary FA rel
ated to physiological or pathological processes.