Yes, the Lively Living ultrasonic diffuser does not use any form of heat, candle or naked flame, so it is even safe around children, the elderly and pets. The diffuser will automatically switch off once the water level reaches a low level (up to 4 hours for the Aroma-Joy, and 10/18 Hours for the NEW Aroma-Bloom). We actually encourage you to sleep with you diffuser on, and leave the diffuser operating when you leave your home, so you will come back to a purified environment.