OBJECTIVE--To study the prevalence and the characteristics of physiological valve regurgitation. DESIGN--Pulsed wave Doppler echocardiography, continuous wave Doppler echocardiography and Doppler colour flow mapping were performed prospectively in healthy volunteers. SETTING--Echocardiography laboratory in a city hospital. PATIENTS--32 consecutive healthy volunteers (age 21-49 years, mean age 29.4). MAIN OUTCOME MEASURES--Identification of regurgitation with colour Doppler flow mapping and measurement of the jet area, jet length, and maximal velocity of the regurgitation. RESULTS--Regurgitation was recorded at the pulmonary (100%), tricuspid (100%), mitral (56%), and aortic valves (6%). The velocity of pulmonary and tricuspid regurgitation was similar to that predicted from the pressure gradient calculated from the Bernoulli equation. The jet area and jet length were generally small. CONCLUSION--Trivial regurgitation from the pulmonary, tricuspid, and mitral valves is common in healthy people. It is important to take such regurgitation into account when valve disease is diagnosed.