Julius Michael Millingen (1800–1878) was an English physician and writer. He was one of the doctors treating Byron at his death.
He was born in London on 19 July 1800, a son of James Millingen. He spent his early years in Calais and Paris, and was sent to school in Rome. In holidays he took walking tours in Germany, on one of which he is said to have visited Goethe in Weimar. In 1817 he entered the University of Edinburgh, and attended medical classes there until 1821, when he received a diploma from the Royal College of Surgeons of Edinburgh.
When the London Philhellenic Committee was formed, Millingen was recommended to it by William Smith, and on 27 August 1823 he left England for Corfu, with letters of introduction to the Greek government and to Lord Byron. Arriving at Asos in Cephalonia in November of that year, he found Byron at Metaxata, and spent some time with him there. He later accompanied him to Missolonghi, and attended him in his last illness, which, at the autopsy, Millingen pronounced to be purulent meningitis He was accused by Francesco Bruno, another of Byron's doctors, in an article in the Westminster Review, with having caused his death by delaying phlebotomy. Millingen replied at length in his Memoirs. A modern view is that both doctors were culpable in Byron's death, for their use of bleeding.
Soon after Byron's death in 1824, Millingen had a severe attack of typhoid fever; on recovering he was appointed surgeon in the Greek army, in which he served until its surrender to the Turks. He was taken prisoner by Ibrahim Pasha, and released only after representations by Stratford Canning, then British ambassador to the Sublime Porte. In November 1826 Millingen went to Smyrna, and after a short stay in Kutaya and Broussa, settled in 1827 in Constantinople. There he attained a reputation as a physician.