Nobel Prize in Medicine in 1966..Peyton Rous is the oldest person to get the award in Medicine.

Peyton Rous

Charles Brenton Huggins

The Nobel Prize in Physiology or Medicine 1966 was divided equally between Peyton Rous "for his discovery of tumour-inducing viruses" and Charles Brenton Huggins "for his discoveries concerning hormonal treatment of prostatic cancer"

Nobel Prize 1987 for Medicine or Physiology.

Susumu Tonegawa

The Nobel Prize in Physiology or Medicine 1987 was awarded to Susumu Tonegawa "for his discovery of the genetic principle for generation of antibody diversity".