In 82 patients with Bell's palsy nerve excitability test (NET) and electrogustometry (EGM) were performed and the stapedius muscle reflex (SMR) was measured on the day of admission. The comparison of test results with the final outcome of the disease allowed the following observations: in cases with normal SMR a soon and complete regeneration may most probably be expected. The EGM seems to be of prognostic value during the first couple of days after onset only; together with a loss of stapedial function a threshold difference of 15 EGU or more indicates an unfortunate course of the disease. The NET does not say anything about prognosis before the third day after onset. When the threshold of electrical excitability on both sides differs 3.5 mA or more an incomplete recovery has strongly to be expected; however, during the first two weeks a normal excitability does not exclude an incomplete recovery; only after that time such finding means a good prognosis. Those cases with pathological results in all three function tests made a--sometimes severe--defective recovery. These observations suggest, that the above function tests supplement each other very well and that a combined application of these tests can improve prognostic evaluation of Bell's palsy. It seems of special value that by means of these tests cases with a bad prognosis may be already recognized on the third or fourth day after onset with a relatively high reliability.