Bayer is a multinational pharmaceutical and life science company based in Germany. Bayer has operations around the globe in the fields of consumer healthcare, pharmaceuticals, crop science and animal health. It has been most well-known for products in women’s health, particularly contraceptives but has a range of products in other therapeutic areas including cardiology, radiology, and oncology. In 2018, Bayer acquired agrochemical company, Monsanto and its controversial product, Roundup.

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Bayer Group

The Bayer Group is a German corporation focused on the life science fields of biotechnology, healthcare and agricultural science. It is the parent company for 374 consolidated companies with operations in 83 countries which includes operations in the U.S. in Consumer Health, Crop Science and Pharmaceuticals.

Bayer has over 99 thousand employees worldwide. In 2021, the Bayer Group had estimated global revenue of $44 billion with Bayer pharmaceutical division bringing an estimated $19 billion.

Bayer U.S. has three operating units:

  • Consumer Health – over-the-counter-medicines, supplements, and prescription dermatology products
  • Pharmaceuticals – prescription medications in cardiology and hematology, oncology, neuroscience, infectious diseases, and men’s and women’s health
  • Crop Science – high-value seeds, chemicals, and pest management solutions much of which was acquired in a 2016 acquisition of Monsanto

The Bayer U.S. pharmaceutical division manufactures successful medications such as:

  • Betaseron – interferon for Multiple Sclerosis
  • Cipro – ciprofloxacin fluorquinolone antibiotic
  • Gadavist, Eovist – gadolinium radiopaque for imaging procedures
  • Mirena, Kyleena, Skyla – levonorgestrel hormonal IUD
  • Nexavar, Viktrakvi – sorafenib monoclonal antibody cancer treatment
  • Yaz / Yasmin – hormonal birth control
  • Kogenate, Kovaltry, Jivi – recombinant antihemophiliac medications

Some of these medications are no longer manufactured by Bayer due to divestments or discontinuation.

Several of Bayer’s pharmaceutical products have resulted in multiple personal injury lawsuits. The progesterone ingredient in Yaz and Yasmin (and Beyaz) has been linked to an increase in the risk of fatal blood clots and Mirena has caused uterine perforation in some women.

History of Bayer

Bayer was founded in 1863 to manufacture and sell synthetic dyes for the textile industry in Germany but by 1913, the company had operations in Russia, France, Belgium, the UK and the United States and had expanded beyond textiles into chemicals and pharmaceuticals. During World War I, sales of dyes and pharmaceuticals dropped dramatically due to frozen export markets and the company began producing war materials such as explosives and chemical weapons. During the war, most of the foreign assets were lost or confiscated such as U.S. patents and trademarks including heroin and aspirin.

Bayer became a part of I.G. Farbenindustrie AG in the mid 1920’s due to changing global markets and economies, developing synthetic rubber and polyurethanes but discovering sulfonamide antibiotics in the process. I.G Farben was split into 12 companies by the Allied Forces, leading to the reemergence of Bayer in 1951 as Farbenfabriken Bayer AG.

Under Allied control, Bayer was allowed to reestablish international sales activities and focused on the U.S. and Latin America as well as expanding operations in Germany and Europe. During this period, Bayer continued development on the chemical and agricultural products but also introduced cardiovascular medicines, antifungals, and antibiotics.

In the 1970’s, the company acquired U.S. based Cutter Laboratories and Miles Laboratories which allowed Bayer to gain position in the U.S. pharmaceutical market. Bayer’s research labs produced the cardiovascular drug Adalat and the first quinolone antibiotic Cipro which were marketed in the U.S. under the Miles name.

In 1994, after the radical political changes had taken place in Germany and Eastern Europe, Bayer acquired U.S. based Sterling Winthrop, a self-medication company which came with regained access to the Bayer name in the U.S. For the first time in 75 years, Bayer could use its own name and logo in the United States and Miles Inc. was renamed Bayer Corporation.

In 2001, Bayer began a long period of reorganization, establishing operating units as independent subsidiaries under the Bayer Group Umbrella. In 2005, Bayer acquired the consumer products division of Roche, making it one of the world’s top three non-prescription medication manufacturers. In March of 2006, Bayer announced a public takeover of Schering AG and renamed the company Bayer Schering AG. Bayer Schering is later completely incorporated into Bayer Healthcare.

In 2014, Bayer acquired Merck & Co.’s consumer healthcare business, adding a number of over-the-counter medications and products such as Claritin and Coppertone and in 2018, Bayer acquired Monsanto, producer of Roundup herbicide and a number of high-value, GMO crops and pesticides.

Most recently, Bayer acquired Asklepios BioPharmaceutical which launched a new platform for cell and gene therapy. Bayer has also divested its Diagnostics, Diabetes Devices, Chemicals, Material Science and Animal Health divisions.

Since 2007, Bayer has been notably active in environmental awareness, children’s issues, women’s health, and other social projects, receiving multiple awards and accolades including a celebratory meal with German Federal Chancellor Angela Merkel in 2013 at its 150th anniversary. The company announced in 2020, that it would significantly step-up “sustainability efforts”.

Bayer Product Issues

Bayer has a history of innovation and healthcare solutions but has faced challenges with some of its products. Other issues have been inherited through some of its acquisitions, most recently with Bayer’s acquisition of Monsanto, manufacturer of Roundup (glyphosate) herbicide.


Bayer chemists Heinrich Dreser and Felix Hoffman produced diacetylmorphine; an acetylated form of morphine that was believed to be less addicting for use as a cough suppressant. It was named “heroin” and was introduced in 1898 exported to 23 different countries including the U.S. By 1913, the company had stopped manufacturing the medication after numerous reports of hospitalizations and abuse. During World War I, Bayer’s U.S. and other foreign assets, patents and trademarks were seized but the introduction of heroin had started an avalanche of addiction and it was outlawed by Congress in 1920.

Yaz Oral Contraceptives

Bayer has produced several oral contraceptives with the progesterone type ingredient, drospirenone. Drospirenone is contained in the birth control pills Yaz, Yasmin, Yasminelle, several generic versions, including Ocella, a newer contraceptive, known as Beyaz and a medication to manage menopausal symptoms, Angeliq. Studies have shown that drospirenone may triple the risk of blood clot formation from deep vein thrombosis, which may result in pulmonary embolism, stroke, or heart attack and may cause death.

Yaz was introduced in 2006 and has resulted in multiple disciplinary warnings by the FDA regarding advertising practices. The FDA has required drospirenone containing products to include warnings regarding a higher risk of dangerous blood clots and stopping the medication before surgery.

Over 20,000 lawsuits have been filed against Bayer because of Yaz and Yasmin side effects. By 2016, the company had settled 10,300 blood-clot lawsuits for $2 billion, 7,200 gallbladder injuries for $22 million, and 1,200 claims of stroke and heart attack for $57 million. While many lawsuits have been settled for Yaz injuries, hundreds may still remain in federal, state, and local courts.


Mirena is a hormone-emitting intrauterine device or IUD. It is a reversible form of birth control that may cause pelvic inflammatory disease, device expulsion, or ectopic pregnancy. The greatest danger is apparently caused by device migration from its placement location to perforate the uterine wall.

It may also endanger abdominal organs or blood vessels and expose the patient to infection, pain, and permanent organ damage and several women have recently claimed that Mirena caused neurological conditions because of the hormone levonorgesterel, eluted from the device.

An estimated 10 thousand lawsuits have been filed against Bayer by injury caused by Mirena. Mirena lawsuits have included claims of device migration/organ perforation, Pseudotumor Cerebri (intracranial pressure), and other concerns. Many of these lawsuits were consolidated into two federal multidistrict litigation (MDL) groups in New York and while some were dismissed, a $12.2 million settlement covered about 4,000 cases. Others still remain in federal, state, and local court systems, including a state multicounty litigation (MCL) group in New Jersey.


Essure was a non-surgical permanent birth control method introduced in 2002, by private-company, Conceptus, which was acquired by Bayer in 2013. It was a revolutionary, non-hormonal method of birth control and was initially, successful, serious side effects became common.

Serious Essure bleeding and side effects resulted in formation of a number of patient support groups and a 2018 Netflix documentary “The Bleeding Edge”. The device was restricted in 2018 to physicians and clinics who ensured that women would be informed of the risks, but Bayer announced Essure’s discontinuation in December 2018.

Thousands of women have filed lawsuits against Conceptus and later, against Bayer for serious complications caused by Essure. Lawsuits have claimed that the devices caused serious injury including excessive bleeding, infection, device migration, ectopic pregnancy, and perforation of uterus, fallopian tube, bladder, or bowels.

In August 2020, Bayer announced that they would settle most of the nearly 40,000 lawsuits for about $1.6 billion.


In 2018, Bayer acquired agricultural and chemical giant, Monsanto. With the acquisition, Bayer assumed liability for one of Monsanto’s flagship products, Roundup. Roundup is the brand name of the chemical, glyphosate, which is an herbicide that has seen wide-spread use in agriculture, industry, business and commercial lawn management and home property maintenance.

Roundup’s primary ingredient, glyphosate has been linked to a type of cancer, non-Hodgkin’s lymphoma, along with possible links to other types of cancer. In 2015, the World Health Organization (WHO) agreed that the product “probably” caused cancer. This was later echoed by other organizations including the U.S. Centers for Disease Control (CDC), and the product was banned from some countries around the world.

Monsanto, and now Bayer have faced thousands of lawsuits filed by people or family members of those who were diagnosed with Roundup-related cancer. Juries have awarded a couple $2 billion, $289 million for a second case and verdict was given for $80 million in a third trial, the three verdicts were later reduced to a total $190 million. In 2020, the company agreed to settle about 80% of the outstanding Roundup lawsuits for $8 billion and to set aside $2 billion for future lawsuits that may number over 125,000. In 2020, the CDC released a study showing that 8 out of 10 people in the U.S. have glyphosate in their urine. In addition to other types of cancer, Roundup has also been linked to Parkinson’s disease and other neurological disorders. Bayer may also be facing future lawsuits for other agricultural products including a claim that dicamba herbicide caused a massive loss of honeybees.