Inside Unit 731, World War II Japan’s Sickening Human Experiments Program

Published November 2, 2017
Updated November 5, 2018

Syphilis Experiments

Shiro Ishii

Wikimedia CommonsGeneral Shiro Ishii, the commander of Unit 731.

Venereal disease has been the bane of organized militaries since ancient Egypt, and so it stands to reason that the Japanese military would take an interest in the symptoms and treatment of syphilis.

To learn what they needed to know, doctors assigned to Unit 731 infected prisoners with the disease and withheld treatment to observe the uninterrupted course of the illness. A contemporary treatment, a primitive chemotherapy agent called Salvarsan, was sometimes administered over a period of months to observe the side effects, however.

To ensure effective transmission of the disease, syphilitic male prisoners were ordered to rape both female and male fellow prisoners, who would then be monitored to observe the onset of the disease. If the first exposure failed to establish infection, more rapes would be arranged until it did.

Rape And Forced Pregnancy

Harbin Facility

Wikimedia CommonsUnit 731’s Harbin facility.

Beyond just the syphilis experiments, rape became a common feature of Unit 731’s experiments.

For example, female prisoners of childbearing age were sometimes forcibly impregnated so that weapon and trauma experiments could be done on them.

After being infected with various diseases, exposed to chemical weapons, or suffering crush injuries, bullet wounds, and shrapnel injuries, the pregnant subjects were opened up and the effects on the fetuses studied.

The idea seems to have been to translate the teams’ findings into civilian medicine, but if Unit 731’s researchers ever published these results, the papers seem not to have survived the war years.

Richard Stockton
Richard Stockton is a freelance science and technology writer from Sacramento, California.