Monsanto, American corporation that was a leading producer of chemical, agricultural, and biochemical products. After being acquired byBayer in 2018, it ceased to exist as an entity.

The Monsanto Chemical Works was founded in 1901 byJohn F. Queeny (1859–1933), a purchasing agent for a wholesale drug company, to manufacture the synthetic sweetenersaccharin, then produced only in Germany. Queeny invested $1,500 of his own money and borrowed another $3,500 from a local Epsom salts manufacturer to launch his new company, which he named Monsanto, after his wife’s maiden name. The firm was up to full-scalesaccharin production in 1902, addedcaffeine and vanillin to its product line over the next few years, and in 1905 began turning a profit. With theCoca-Cola Company as one of Monsanto’s chief customers, sales reached $1 million in 1915. Monsanto began producingaspirin in 1917.

Like many other American chemical companies, Monsanto expanded duringWorld War I and flourished under the protection of the high U.S. tariffs of the 1920s. Queeny passed control of the company to his son,Edgar M. Queeny (1897–1968), in 1928. Edgar Queeny transformed Monsanto into an industrial giant before he retired in 1960. The company was incorporated as the Monsanto Chemical Company in 1933. Its production ofstyrene, a component of synthetic rubber, was vital to the U.S. war effort duringWorld War II. Reflecting its diverse product offerings, the company changed its name to Monsanto Company in 1964. In 1985 Monsanto purchased pharmaceutical firm G.D. Searle & Co., maker of the NutraSweet artificial sweetener. Monsanto sold its sweeteners businesses, including NutraSweet, in 2000.

In the 1990s Monsanto’s acquisition of Calgene Inc., DEKALB Genetics, and otherbiotechnology firms made it a leader in the development and production of genetically modified crop seeds. It began commercial production of BST (bovine somatotropin), a synthetic supplement for dairy cows, in 1994. Monsanto merged with global pharmaceutical company Pharmacia & Upjohn in March 2000, but in August 2002 Monsanto’s nonpharmaceutical segments were spun off by Pharmacia Corporation, and Monsanto became a publicly traded company. Its primary businesses were in agriculture and biotechnology. To further those interests, it acquired variousseed companies and software firms in the early 21st century.

During this time Monsanto began to be perceived in a negative light by the public. There was opposition to its promotion ofgenetically modified organisms, and the company was involved with chemicals that were alleged to cause health issues. In the 2010s numerous lawsuits were filed claiming that its weed killerRoundup, which contained glyphosate, caused cancer. Against this backdrop, in 2016Bayer, a German chemical and pharmaceutical company, announced that it was purchasing Monsanto in a deal valued at more than $60 billion. In 2018 the acquisition was finalized, and shortly thereafter the first Roundup lawsuit was decided in favour of the plaintiff. Faced with the possibility of extensive legal liabilities, Bayer saw its value decline. Later that year Monsanto was folded into Bayer’s crop science division. In 2020 Bayer agreed to pay more than $10 billion to settle claims regarding Roundup.