Abstract: Scalp cooling apparatus is describe in which an air flow is recirculated so as to reduce entrained moisture to that initially in the air circuit and to the direct contribution of moisture resulting from evaporation from the scalp, and by matching the impedance between the delivery tubing and evaporation orifice for warm incoming air and chilled outgoing air. In one arrangement an applicator helmet has an air delivery gallery which directs air onto the scalp and hairline through a number of profile drillings of such size and profile as to minimize frictional losses in the air stream. Air is extracted at the crown of the helmet where the convergence and increasing air velocity compensates for increased air temperature so that at this point, scalp cooling is optimized by using the wind-chill effect. The interior of the helmet includes a number of spacers which are held in gentle contact with the scalp by applying a slight force in the helmet using a counter-balanced arm.