[43] For the rest of the late 19th century, Lilly operated in Indianapolis and the surrounding area as many other pharmaceutical businesses did, manufacturing and selling "sugar-coated pills, fluid extracts, elixirs, and syrups".

One historian noted, "Although the Indianapolis firm was more careful in making and promoting drugs than the patent medicine men of the era, the company remained ambivalent about scientific research.

"[51] Eli Lilly and Company enjoyed an effective monopoly on the sale of insulin in the U.S. for almost two years, until the first of the new American licensees, Frederick Stearns & Co., entered the market in June 1924.

[42] In 1928, Lilly introduced Liver Extract 343 for the treatment of pernicious anemia, a blood disorder, in a joint venture with two Harvard University scientists, George Minot and William P. Murphy.

[77] In the 1950s and 1960s, as generic drugs began flooding the marketplace after the expiration of patents, Lilly diversified into other areas, including agricultural chemicals, veterinary medicine products, cosmetics, and medical instruments.

To further diversify its product line, Lilly made an uncharacteristic, but ultimately profitable move in 1971, acquiring cosmetic manufacturer Elizabeth Arden, Inc. for $38 million.

[83] In 1977, Lilly ventured into medical instruments with the acquisition of IVAC Corporation, which manufactures vital signs and intravenous fluid infusion monitoring systems.

Other acquisitions included Advance Cardiovascular Systems in 1984, Hybritech in 1986, Devices for Vascular Intervention, in 1989, Pacific Biotech in 1990, and Origin Medsystems and Heart Rhythm Technologies, in 1992.

[88] Lilly sold companies in its Medical Device and Diagnostics Division, expanded international sales, made new acquisitions, and funded additional research and product development.

[94][97][98] In January 2009, the largest criminal fine in U.S. history, totaling $1.415 billion, was imposed on Lilly for illegal marketing of its best-selling product, the atypical antipsychotic medication, Zyprexa.

[100] Boehringer Ingelheim's oral anti-diabetic Linagliptin, BI 1077, and two of Lilly's insulin analogs, LY2605541 and LY2963016, were in phase II and III of clinical development at that time.

In April 2014, Lilly announced plans to acquire Switzerland-based Novartis AG's animal health business for $5.4 billion in cash to strengthen and diversify its Elanco unit.

[105] In April 2015, Lilly engaged CBRE Group to sell its biomanufacturing facility in Vacaville, California,[106] a 52 acres (0.21 km2) campus and facility that is one of the largest biopharmaceutical manufacturing centers in the U.S.[106] In January 2017, Elanco Animal Health, a subsidiary of the company completed the acquisition of Boehringer Ingelheim Vetmedica, Inc., a subsidiary of Boehringer Ingelheim's U.S. feline, canine, and rabies vaccines portfolio.

[123] The same month, Lilly announced it would acquire Disarm Therapeutics and its experimental treatments for axonal degeneration, via SARM1 inhibitors, for $135 million plus a further $1.225 billion based on regulatory and commercial milestones.

[125] In November 2020, the FDA issued an emergency use authorization (EUA) for the investigational monoclonal antibody therapy bamlanivimab for the treatment of mild-to-moderate COVID-19 in adult and pediatric patients.

[132] A second COVID-19 monoclonal antibody therapy, bebtelovimab, developed with AbCellera, was granted Emergency Use Authorization in February 2022, with the U.S. government committing to a $720 million purchase of up to 600,000 doses.

[33][150] After World War I, the company's expanded production facilities and introduction of new management methods set the stage for Lilly's next crucial phase—its "aggressive entry into scientific research and development.

[211] Among the company's other pharmaceutical developments are cephalosporin, erythromycin, and Prozac (fluoxetine), a selective serotonin reuptake inhibitor (SSRI) for the treatment of clinical depression.

[citation needed] In March 2023, Eli Lilly announced a $35 cap on the price of monthly insulin to be put in place immediately in order to be in line with the Inflation Reduction Act.

[212] Medications that provide significant revenue for Lilly include Trulicity, Mounjaro, Verzenio, Taltz, Jardiance, Humalog, Cyramza, Olumiant, Emgality, Tyvyt, Retevmo, Alimta, and Zepbound.

[citation needed][218] Lilly was the first distributor of methadone in the United States, an analgesic used frequently in the treatment of heroin, opium and other opioid and narcotic drug addictions.

Secobarbital is indicated for the treatment of epilepsy, temporary insomnia and as a pre-operative medication to produce anesthesia and anxiolysis in short surgical, diagnostic, or therapeutic procedures which are minimally painful.

[37] In 1917, Lilly Field Hospital 32, named in Josiah's honor, was equipped in Indianapolis and moved overseas to Contrexville, France, during World War I, where it remained in operation until 1919.

[37] Throughout World War II, Lilly manufactured more than two hundred products for military use, including aviator survival kits and seasickness medications for the D-Day invasion.

[236] In August 2008, Eli Lilly purchased the right to manufacture bovine growth hormone, used to increase milk production in dairy cattle, from Monsanto.

[248] Eli Lilly has faced many lawsuits from people who claimed they developed diabetes or other diseases after taking olanzapine (branded Zyprexa), an antipsychotic medication, as well as by various governmental entities, insurance companies, and others.

[253] In 2009, four sales representatives for Eli Lilly filed separate qui tam lawsuits against the company for illegally marketing Zyprexa for uses not approved by the Food and Drug Administration.

Eli Lilly pleaded guilty to a US federal criminal misdemeanor charge of illegally marketing Zyprexa, actively promoting the drug for off-label uses, particularly for the treatment of dementia in the elderly.

[260] In September 2021, Eli Lilly and Company was accused in a federal court lawsuit of discriminating against older applicants for sales positions based on their implementation of hiring quotas for millennials.

[261] In September 2013, Eli Lilly sued Canada for violating its obligations to foreign investors under the North American Free Trade Agreement by allowing its courts to invalidate patents for Strattera and Zyprexa.