He spent some time serving under Albert Schweitzer at Lambaréné in French Equatorial Africa (now Gabon), and travelled to the United States in 1957–8 under a Carnegie Fellowship, and started to specialise in endocrinology. He obtained his MD in 1957 and PhD in 1968. He was a lecturer at the Department of Medicine at the University of Cape Town from 1955 to 1967. He also continued to practise medicine at Groote Schuur Hospital, where he was involved preparing for Christiaan Barnard's first heart transplant operation in 1967.