In 1935 Allum was charged with posing as a medical practitioner while not registered under the Medical Practitioners Act. Allum defended himself stating that he had never claimed to be a doctor or any other medical practitioner. He was eventually convicted and fined. Allum was convinced that members of the medical profession were behind his prosecution as they were threatened by the fact his patients had become disillusioned with traditional medicine and were more satisfied by his treatments. He considered leaving Australia because of this perceived persecution, but hundreds of happy patients signed a petition asking him not to leave Adelaide. The publicity surrounding the court case only succeeded in bringing in new patients.

Allum married an Australian woman much younger than himself and in 1953 they returned with their daughter to Afghanistan to live. Shortly afterwards Allum's wife died of smallpox and he and his daughter returned to Adelaide in 1954, where he resumed practicing as a herbalist.

Allum published many pamphlets about health matters as well as about Islam and the Koran, although he did not read or write English. He did not ask for payment for his services but left it to patients to pay what they felt they could afford. He donated much of his income to charities and often provided food for the poor of Adelaide.