When drug or other therapeutic research reaches the stage when it is ready for human trial on a controlled, scientifically-observed experimental basis, particularly under conditions of segregation, the prison population is often turned to. Experimentation in jails and penitentiaries may be done without the prisoners knowledge and consent, or with consent but with little or no understanding of the risks involved. In some cases the experiments are dangerous, the risks being surgical mutilation, pharmaceutically or chemically induced organ impairment, or personality disorders.
During World War II, the Nazis experimented on prisoners in concentrations camps and the Japanese experimented on prisoners of war. Prisoners have been used in widespread fashion all over the USA in therapeutic drug trials and other medical and behaviour experiments.
In the 1960s, the USA treated prisoners' skin with chemical agents in the hope they would cause significant inflammation and crusting. The experimentation was to discover if skin could be toughened sufficiently to provide natural body armour for soldiers.