He was portrayed by the late George Coulouris in the 1974 film adaptation, voiced by Nolan North in the 2006 video game adaptation, and portrayed by Samuel West in the 2010 television film adaptation in Agatha Christie's Poirot.
Dr. Constantine is a Greek physician who helped Hercule Poirot by examining Ratchett's dead body and accumulating all the scientific facts. He is described as a small, dark man. On the Orient Express, he travels in the Athens-Paris coach.
After the death of Samuel Ratchett, Dr. Constantine assisted Poirot and Monsieur Bouc to find the killer on the train, before they discovered Ratchett's true identity as Lanfranco Ratchett, a notorious kidnapper who was resposible for the kidnap and death of Daisy Armstrong, but had got away.
After the killers were revealed to be other 12 passengers, who were more or less related to the Armstrong family and desired to kill Cassetti for justice, Constantine supported Bouc's idea and adviced Poirot to let the killers gone free, whilst he would do some rig on medical report to hide about the truth, due to sympathizing the killers and their motives to seek justice.
In other adaptations
In 2010 film
In this adaptation, which omitted the role of Cyrus Hardman, Dr. Constantine became one of the twelve killers instead. Here, he was a Greek-American obstertrician from Long Island, who took care of Sonia Armstrong until she died of miscarriage due to Daisy's demise. Enraged by Cassetti's crime and became sympathized with the Armstrongs, Dr. Constantine decided to join the murder.
During the investigation, Dr. Constantine faked the crime scene, making others believe that a fictional mobster who killed Cassetti hadg escaped from a window. He also tried to misled Poirot, but it proved to be a failure. By the end of the film, he was shown to be in surprise and disbelief when Poirot decided to spare all of the killers.
In 2017 film
- Main article: Dr. Arbuthnot
In the 2017 film adaptation, Dr. Constantine was omitted, with his occupation as a physician was adaptated on this version of Colonel Arbuthnot (who was called Dr. Arbuthnot in this version) and was depicted as an African-American. Still, personality-wise, this Dr. Arbuthnot is more like an incarnation of Colonel Arbuthnot in the novel, instead of Dr. Constantine in the novel.