Whether temperature, pH, osmotic pressure, Ca2+, Mg2+, and ATP have promotive effects on ciliary activity was investigated by a photo-electric method using cultured human ethmoid sinus mucosa. The results obtained were as follows: 1. Ciliary activity was reversible between 11 and 43 degrees C. It was activated with rising temperature, and inactivated at 40 degrees C. A temperature between 36 and 40 degrees C was optimal for activation of ciliary activity. 2. In the case of brief immersion (30 min.) in solutions between pH 4.5 and 8.5 ciliary activity was reversible, and with prolonged immersion (72 h) between pH 6.5 and 7.5 it was also reversible. with brief immersion within 30 min, pH 8.5 was an activating factor. 3. Ciliary activity was reversible in solutions between 143 and 1,140mOsm/Kg for 30 min. However, the ciliary reaction was different even at the same osmotic pressure according to the substance, NaCl or glucose, used to adjust it. Inhibited beating was reversible after prolonged immersion (72 h) in an osmotic pressure between 285 and 423mOsm/Kg adjusted by NaCl, and between 285 and 570mOsm/Kg adjusted by glucose. Any osmotic pressure of 428mOsm/Kg adjusted by NaCl activated ciliary activity. 4. Neither Ca2+ nor Mg2+, between 10(-2) and 10(-6) Mol, increased ciliary activity. 5. Between 10(-3) and 10(-5) Mol of Na-ATP, given exogenously, slightly activated ciliary movement, while Mg-ATP of 10(-3) Mol also activated it but only slightly. It is important to bear in mind the above results in administering local aerosol therapy for nasal and paranasal sinus diseases.