Groth began his career at
Serafimer Hospital in Stockholm, working in the department of surgery. He gained a PhD in 1965 with a thesis on
red blood cell aggregation in trauma. After deciding to focus on
transplantation surgery, Groth was awarded a research fellowship from the United States
National Institutes of Health to study transplantation at the
University of Colorado under the supervision of
Thomas Starzl. When Starzl performed the first successful human
liver transplantation in 1967, Groth was his surgical assistant. While in Colorado, Groth researched liver and
lymphoid tissue transplantation in dogs, and made several important contributions to transplantation medicine, including the use of
anti-lymphocyte globulin (ATG) use in
acute organ rejection and the "triple-drug"
immunosuppression regimen for post-transplantation patients including ATG,
azathioprine and
prednisone. Groth returned to Stockholm in 1972, when he was chosen by
Curt Franksson to head the transplantation program at the newly founded Huddinge Hospital (now
Karolinska University Hospital). ==Personal life and death==