What is a ceramic diffuser and how to use it? Diffusers are necessary for anyone who uses essential oils, but so many models are available that can be confusing. No need to worry; here you will find detailed instructions on how to use an essential oil ultrasonic ceramic diffuser and learn more about how to diffuse oils to enhance your health and wellbeing. The use of essential oils has gained popularity among those who practise natural living, but inhaling scented vapours has been practised for thousands of years. The Greeks employed the technique to improve their athletes' physical and mental conditions. Today, a wide range of illnesses are treated with aromatherapy.