From the concepts of well known ototoxic effects of loop diuretics and hypoxic state, twenty guinea pigs with diuretics and/or hypoxia were evaluated with click-evoked otoacoustic emissions(CEOEs) by time-sequential monitoring. Furosemide 25mg/kg was injected to 8 guinea pigs and CEOEs were measured at pretest, 5 minutes after injection, 10, 20, 30, 45 and 60 minutes after the injection. Both echo responses(ER) and reproducibilities(RE) were decreased significantly at 10 minutes after injection, showed the minimal level at 20 minutes. Recovery evidences of CEOEs were noticed by the spectral analysis at 30 minutes after injection, and full recovery of CEOEs was noticed after then. At 60 minutes after injection, the anorexia of 20 seconds by stopping off the artificial respirator was added. The CEOEs showed statistically significant decrease compared to those of preanoxic stage. The CEOEs of 8 guinea pigs with injection of furosemide 50mg/kg showed the decreased ER and RE and no recoveries were noticed for 60 minutes' observation. From this study, clinical application of CEOEs as an objective cochleogram for an early detection of various ototoxicities were expected.