This question is pertaining to black servicemen prior the the desegregation of the US military.
Were black American soldiers who were injured in combat treated by white or black nurses while in hospital?
During World War II, the answer overwhelmingly would have been white, but African-American nurses were utilized up to the point that quotas would allow. The Army nominally restricted African-American nurses to caring for African-American troops in segregated wards or hospitals (essentially all of which were in communications zone or "backwater" areas or in the continental United States), and in certain cases, for German prisoners of war. The Army Nurse Corps, founded in 1901, was not opened to African-Americans until January 1941, and then only on a quota basis of 56. This quota was raised to 160 by 1943. In June 1943, Congresswoman Frances Payne Bolton (R-OH) proposed an anti-discrimination amendment to a nurse training bill that was then making its way through Congress, and on 15 June 1943, the bill, regarding the disbursement of funding for the training of nurses for national defense purposes at civilian institutions was passed; section 1 prohibited racial discrimination by institutions taking part in the program. In December 1942, Army nurses received full officers' pay (the same as a man of the same rank with no dependents) even though they still only held "relative rank," equivalent to a man holding the same rank in some aspects, but with limited authority privileges and (previously) lesser pay. In June 1944, Army nurses were authorized to be commissioned as officers in the Army of the United States and receive full benefits and retirement privileges. Increasing political pressure caused the Army to abandon the quota system for African-American nurses entirely in July 1944, and 2,000 African-American women soon entered the uniformed Cadet Nurse Corps (created by the act of 15 June 1943). Only 479 had received commissions by September 1945, however. African-American women were also permitted to serve in the Women's Army Auxiliary Corps (WAAC) and Women's Army Corps (WAC), but were limited by Army regulations that only permitted them, along with male African-American soldiers, to be recruited up to African-Americans' share of the U.S. population at the time (roughly 10 percent); 6,520 African-Americans served in the WAC/WAAC.
Sources:
Bellafaire, Judith The Army Nurse Corps: A Commemoration of World War II Service. Washington, D.C.: United States Army Center of Military History.