A micro-humidifier for operably-connecting to a breathing circuit contains a liquid feed, a liquid chamber operably-connected to the liquid feed, and a vapour generator operably-connected to the liquid chamber. The liquid chamber has a volume of from about 0.01 mL to about 30 mL. The micro-humidifier is operably-connected to and/or is designed to be operably-connected to a breathing circuit upstream of the patient. When the micro-humidifier is operably-connected to a breathing circuit, the vapour from the vapour generator enters into the breathing circuit. A respiratory humidification system contains the a breathing circuit and the micro-humidifier as described herein. The micro-humidifier is operably-connected to the breathing circuit upstream of the patient, and the vapour from the vapour generator enters into the breathing circuit.
