A sangoma is a practitioner of herbal medicine, divination and counselling in traditional Nguni (Zulu, Xhosa, Ndebele and Swazi) societies of Southern Africa (effectively an African shaman). The philosophy is based on a belief in ancestral spirits. Both men and women can be called by the ancestors (a consequence of refusing the calling is usually ongoing physical or mental illness). A trainee sangoma (or twaza) trains under another sangoma, usually for a period of years, usually performing humbling service in the community.