Richard McConnell, who has died in his native city of Liverpool aged 83, was a consultant physician of international reputation, and a pioneer in genetics and gastroenterology. He was also a generous and charming man, who could never refuse to help anyone, including Saddam Hussein, whom he treated for a stomach complaint after a special request in Baghdad in the 1970s.

The son of a local GP, he attended St Christopher's school and Liverpool College. At the age of 16, he went to Liverpool University, qualifying as a doctor in 1942. As a squadron leader in the RAF, he saw three years of wartime service in north Africa and Italy.

After returning to Liverpool, McConnell began work as a house officer at the David Lewis Northern hospital, gaining his MD in 1955. He was appointed consultant physician to the Stanley hospital, Bootle, and, later, the Liverpool Royal infirmary and Broadgreen hospital.

This was a period of great activity, with much travel to the US, where he researched the relationship between smoking and lung cancer, as well as discussing with Dr (later Sir) Cyril Clarke the genetics of duodenal ulcers.

In Philadelphia in 1958, he saw the new fibre-optic scopes, and went on to develop the first purpose-built gastroentrology unit in Britain, at Broadgreen hospital. In 1963, his fibre-optic gastroscope was only the second in the UK.

McConnell was a prolific writer, publishing 47 research papers, as well as standard textbooks such as The Genetics Of Gastro Intestinal Disorders (1966). He was editor of Clinics In Gastroenterology (1973) and one of the four co-editors of The Genetics Of Inflammatory Bowel Disease.

He became president of the British Society of Gastroenterology in 1983, and president of the Liverpool Medical Institution in 1986.

Even in his last illness, he still was full of optimism, telling his family, "I am dying, and it is not so bad." He is survived by his wife Gwenllian, whom he married in 1962, a daughter and two sons.

· Richard Bonar McConnell, medical consultant and author, born January 21 1920; died October 21 2003