Detlef Rathmer (born 1968) is a state-certified alternative practitioner and director of the Sehgal School for Revolutionary Homeopathy (SfRH) in Billerbeck. During his four-year course in naturopathy, he focused in particular on classical homeopathy, eye diagnosis, Bach flower therapy and Schuessler salts.

For several years, Detlef Rathmer has been training alternative practitioners in the fields of naturopathy and conventional medicine. Since 2002, the focus of his practice has been the "holistic treatment of patients using the Sehgal method". In March 2008, his self-taught learning and workbook "Case analysis in homeopathy according to Sehgal" was published by Eva Lang Verlag. The father of two sons and former lawyer sets out his decades of experience as a lecturer and trainer as well as the essence of his own spiritual search in his guide "7 ways to find yourself. The art of living for everyday life" (Mankau Verlag 2008).