Rosemary Greer has been practicing as an accredited Colon Therapist since 2001. She has a background in Nursing in four major hospitals in both London and Australia.

She is certified by the Australian Institute of Health, and is a member of the International Natural Therapists Association (INTA), and the Australian Colon Health Association (ACHA)

Oasis Colon Hydrotherapy uses the De Welles Method of Colon Hydrotherapy. Dr De Welles is internationally known and considered by many to be the the outstanding authority on disorders of the colon and the method for their recovery.The equipment used at Oasis was originally designed by Dr De Welles, and has now been upgraded to include filtered water, automatic temperature control, and medical oxygen infused through the water.