Menegele's experiments included placing subjects in pressure chambers, testing drugs on them, freezing them, attempting to change their eye color by injecting chemicals into children's eyes, and amputations and other surgeries.  Other experiments took place at Buchenwald , Dachau , Natzweiler , Neuengamme , Ravensbrück , Sachsenhausen , and elsewhere. Some dealt with sterilization of men and women, the treatment of war wounds, ways to counteract chemical weapons, research into new vaccines and drugs, and survival of harsh conditions. At least 7000 prisoners were subjected to these experiments; most died during them or afterwards. 
The concept people call “Holocaust-Denial” means an affirmation concerning the manner in which normal hygiene technology worked, namely the opposite of what was affirmed at Nuremberg in 1946 – by US/UK military “intelligence” – whereby merely producing a can of Zyklon was taken as evidence of mass human gassing. A remarkable act of amnesia was then accomplished over the hygiene technology which used this product – which later became defunct as DDT replaced it. The ethically damned “denier” is one who realizes that, in response to the arrival of typhus epidemics in the German labour camps in 1942, delousing technology was installed throughout all of the German labour camps, so that safe-to-use cyanide gassing technology killed bugs in all clothing and bedding put into them; and that it didn’t have any other use. No-one at Nuremberg discussed whether the Zyklon-B canisters were for delousing of mattresses or gassing Jews.