A primary cause of death was illness due to harsh camp conditions, with starvation—and its consequent illnesses—prevalent.
Malnourished and suffering from disease, many were literally "worked to death" under the Vernichtung durch Arbeit policy (extermination through labor), as inmates only had the choice between slave labor or inevitable execution.
Many inmates died as a result of human experimentation or fell victim to arbitrary acts perpetrated by the SS guards.
Other prisoners were simply murdered, primarily by shooting and hanging.

Walter Gerhard Martin Sommer was an SS-Hauptscharführer who served as a guard at the concentration camps of Dachau and Buchenwald.
Known as the "Hangman of Buchenwald", he was considered a depraved sadist who reportedly ordered Otto Neururer and Mathias Spannlang, two Austrian priests, to be crucified upside-down.
Sommer was especially infamous for hanging prisoners off of trees from their wrists, which had been tied behind their backs (a torture technique known as strappado) in the "singing forest", so named because of the screams which emanated from this wooded area.

Summary executions of Soviet POWs were also carried out at Buchenwald.
At least 1,000 men were selected in 1941–42 by a task force of three Dresden Gestapo officers and sent to the camp for immediate liquidation by a gunshot to the back of the neck, the infamous Genickschuss.

The camp was also a site of large-scale trials for vaccines against epidemic typhus in 1942 and 1943.
In all 729 inmates were used as test subjects, of whom 154 died.
Other "experimentation" occurred at Buchenwald on a smaller scale.
One such experiment aimed at determining the precise fatal dose of a poison of the alkaloid group; according to the testimony of one doctor, four Soviet POWs were administered the poison, and when it proved not to be fatal they were "strangled in the crematorium" and subsequently "dissected".
Among various other experiments was one which, in order to test the effectiveness of a balm for wounds from incendiary bombs, involved inflicting "very severe" white phosphorus burns on inmates.
When challenged at trial over the nature of this testing, and particularly over the fact that the testing was designed in some cases to cause death and only to measure the time which elapsed until death was caused, one Nazi doctor's defence was that, although a doctor, he was a "legally appointed executioner".
A primary cause of death was illness due to harsh camp conditions, with starvation—and its consequent illnesses—prevalent. Malnourished and suffering from disease, many were literally "worked to death" under the Vernichtung durch Arbeit policy (extermination through labor), as inmates only had the choice between slave labor or inevitable execution. Many inmates died as a result of human experimentation or fell victim to arbitrary acts perpetrated by the SS guards. Other prisoners were simply murdered, primarily by shooting and hanging.
Walter Gerhard Martin Sommer was an SS-Hauptscharführer who served as a guard at the concentration camps of Dachau and Buchenwald. Known as the "Hangman of Buchenwald", he was considered a depraved sadist who reportedly ordered Otto Neururer and Mathias Spannlang, two Austrian priests, to be crucified upside-down. Sommer was especially infamous for hanging prisoners off of trees from their wrists, which had been tied behind their backs (a torture technique known as strappado) in the "singing forest", so named because of the screams which emanated from this wooded area.
Summary executions of Soviet POWs were also carried out at Buchenwald. At least 1,000 men were selected in 1941–42 by a task force of three Dresden Gestapo officers and sent to the camp for immediate liquidation by a gunshot to the back of the neck, the infamous Genickschuss.
The camp was also a site of large-scale trials for vaccines against epidemic typhus in 1942 and 1943. In all 729 inmates were used as test subjects, of whom 154 died. Other "experimentation" occurred at Buchenwald on a smaller scale. One such experiment aimed at determining the precise fatal dose of a poison of the alkaloid group; according to the testimony of one doctor, four Soviet POWs were administered the poison, and when it proved not to be fatal they were "strangled in the crematorium" and subsequently "dissected". Among various other experiments was one which, in order to test the effectiveness of a balm for wounds from incendiary bombs, involved inflicting "very severe" white phosphorus burns on inmates. When challenged at trial over the nature of this testing, and particularly over the fact that the testing was designed in some cases to cause death and only to measure the time which elapsed until death was caused, one Nazi doctor's defence was that, although a doctor, he was a "legally appointed executioner".
Buchenwald concentration camp