Katie Zacharia, US President Donald Trump's new White House press secretary, made claims that the abortion pill contains 'the same chemicals' used in Nazi death camps. Mifepristone blocks progesterone, a hormone needed to sustain pregnancy, while hydrogen cyanide prevents cells from using oxygen to produce energy.

Zacharia, who replaced Karoline Leavitt as White House press secretary, made the claim in an interview about her place on the board of anti-abortion activist Seth Gruber's White Rose Resistance project. She stated that the chemicals 'cut off the oxygen to the baby'.

According to Britannica, approximately 1.1 million people were murdered at Auschwitz, where Zyklon B was used in gas chambers. Mifepristone, by contrast, has been used safely by millions for nearly 40 years, say Johns Hopkins Bloomberg School of Public Health experts.

What the Gas Actually Contained

Zyklon B was a hydrogen cyanide-based pesticide first created in Germany in the early 1920s. Its active ingredient, hydrogen cyanide (HCN), was produced as pellets that turned into a poisonous gas when exposed to air.

Hydrogen cyanide inhibits cytochrome c oxidase, an enzyme essential for cellular respiration, preventing cells from using oxygen to produce energy. This disrupts ATP production and can cause severe tissue damage, particularly in the brain and heart, as well as metabolic acidosis.

Symptoms of cyanide poisoning include dizziness, confusion, rapid breathing and a racing heart. Severe cases lead to coma and death.

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How Mifepristone Really Works

Mifepristone, also known as RU-486, is a synthetic steroid medication developed in France in the 1980s by Roussel-Uclaf. It works by blocking progesterone, the hormone that sustains a pregnancy.

By blocking progesterone, mifepristone disrupts the uterine lining and sensitises the uterus to the effects of prostaglandins. Misoprostol, taken afterwards, stimulates uterine contractions and helps expel the pregnancy.

Planned Parenthood says misoprostol is taken 24 to 48 hours after mifepristone and causes cramping and bleeding similar to a heavy period or early miscarriage. The two-drug regimen can be used at home.

Neither mifepristone nor misoprostol has the same chemical composition as hydrogen cyanide, the poisonous gas released by Zyklon B. Mifepristone contains carbon, hydrogen, nitrogen and oxygen, while misoprostol contains carbon, hydrogen and oxygen. Sharing some chemical elements does not make substances chemically equivalent.

Safety Record Tells Another Story

Mifepristone was approved for use in 1988 and cleared by the US Food and Drug Administration (FDA) in 2000. Nearly four decades of peer-reviewed research have found it to be safe.

Dr Carolyn Sufrin says the risk of serious complications from a medication abortion is below 1 per cent. She adds that only 3 to 5 per cent of patients need further intervention to complete the process.

An FDA report recorded 36 deaths among patients who had used mifepristone for medical termination of pregnancy between September 2000 and 31 December 2024, when an estimated 7.5 million US patients had used the medication. The agency said the reports could not establish with certainty that mifepristone caused the deaths, citing factors including other medical conditions, concurrent medications and gaps in available information.

Dr Suzanne Bell says a pregnancy ending in birth is 14 times more likely to result in maternal death than one ending in abortion. She calls mifepristone one of the most rigorously researched medications.

Corporate Link Fails Chemistry Test

Zacharia posted on X in November 2025 that mifepristone is 'connected to the manufacturer of the deadly gas Zyklon B'.

Degesch held the rights to Zyklon B and was partly owned by I.G. Farben, which held a 42.5 per cent stake. Hoechst, a German chemical and pharmaceutical company that had been part of I.G. Farben, became an independent company again after the conglomerate's post-war breakup.

Hoechst had acquired a majority stake in Roussel-Uclaf, the French pharmaceutical company that developed mifepristone, in 1968. In 1997, after acquiring the remaining shares, Hoechst announced that it would stop producing mifepristone and transfer its rights to the drug to a former Roussel-Uclaf executive.

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