Roussel Uclaf
Former French pharmaceutical company and a predecessor of modern Sanofi.
Last updated August 31, 2026
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Overview
Roussel Uclaf S.A. was a major French pharmaceutical company whose businesses ultimately became part of Sanofi. It operated as one of France’s leading drug manufacturers and, before its absorption into Hoechst, was described as the country’s second-largest pharmaceutical company. The company developed and marketed medicines across several therapeutic areas and also maintained agrochemical activities, making it broader than a narrowly focused prescription-drug business. The company’s most historically consequential contribution was mifepristone, initially designated RU-38486 and later shortened to RU-486. Chemist Georges Teutsch synthesized the compound in 1980 during research into glucocorticoid-receptor antagonists. The molecule also blocked progesterone, leading researchers to investigate its use in medical abortion. Clinical work arranged by endocrinologist Étienne-Émile Baulieu and conducted by gynecologist Walter Herrmann produced early successful results in Switzerland in 1981. Following broader international trials, Roussel Uclaf applied for French authorization of mifepristone used with a prostaglandin analogue in 1987. French approval was announced in September 1988, and the product was marketed in France as Mifegyne. Mifepristone made Roussel Uclaf the focus of intense political, religious, and commercial controversy. In October 1988, following anti-abortion protests and concerns within majority shareholder Hoechst AG, the company’s board voted to halt distribution. The French government ordered the company to resume distribution two days later, treating access to the approved medicine as a public-health matter. Roussel Uclaf subsequently sold Mifegyne to French hospitals and expanded availability to additional European markets. In 1994, the company transferred United States medical-use rights without remuneration to the Population Council. Those rights were later licensed to Danco Laboratories, which obtained U.S. approval for Mifeprex in 2000. Roussel Uclaf’s corporate identity changed as Hoechst increased its control. Its agrochemical operations were transferred in 1994 to Hoechst Schering AgrEvo. Hoechst acquired the remaining Roussel Uclaf shares in early 1997 and completed the company’s absorption into its pharmaceutical structure. The pharmaceutical activities were combined into Hoechst Marion Roussel, while rights to medical uses of mifepristone outside the United States were transferred to Exelgyn, a specialized company led by former Roussel Uclaf chief executive Édouard Sakiz. Hoechst Marion Roussel later merged with Rhône-Poulenc in 1999 to create Aventis; Aventis merged with Sanofi-Synthélabo in 2004, producing the company now known as Sanofi. The agrochemical succession followed a separate path through Aventis CropScience and ultimately Bayer CropScience.
History
Roussel Uclaf emerged as a significant French pharmaceutical enterprise and became one of the country’s principal drug companies. Its activities were not limited to medicines: the business also developed agrochemical operations, reflecting the diversified structure found among several large European chemical and pharmaceutical groups during the twentieth century. By the period before its acquisition by Hoechst, Roussel Uclaf was regarded as France’s second-largest pharmaceutical company. The company’s best-known scientific achievement began with a research program focused on glucocorticoid-receptor antagonists. In April 1980, chemist Georges Teutsch synthesized compound RU-38486, the 38,486th compound synthesized by Roussel Uclaf within the relevant historical numbering sequence. The compound was shortened to RU-486. Researchers subsequently found that it also antagonized progesterone, creating a possible method for terminating an early pregnancy without surgery. Étienne-Émile Baulieu, an endocrinologist who served as a consultant to Roussel Uclaf, helped organize clinical investigation. In 1981, gynecologist Walter Herrmann tested the compound in eleven women at the University of Geneva’s cantonal hospital. The successful results were publicly reported in April 1982. Roussel Uclaf then supported wider clinical development of mifepristone in combination with a prostaglandin analogue. After trials involving about 20,000 women in different countries, the company applied for French authorization in October 1987. Approval for medical abortion was announced in September 1988. The medicine was subsequently marketed in France as Mifegyne. The product immediately became entangled in the abortion debate. Anti-abortion protests and concern from Hoechst AG, which held a majority stake in Roussel Uclaf, led the company’s executives and board to vote in October 1988 to stop distribution. The French government intervened two days after the announcement and ordered the company to continue supplying the drug. French Health Minister Claude Évin framed access as a public-health issue rather than an ordinary commercial decision. After use by approximately 34,000 women in France between April 1988 and February 1990, Roussel Uclaf began selling Mifegyne to French hospitals. The product later received approval in Great Britain in 1991 and Sweden in 1992. Availability expanded slowly because of continuing political opposition. In 1994, Roussel Uclaf transferred all U.S. medical-use rights for mifepristone to the Population Council without remuneration. The council licensed the rights to Danco Laboratories, whose single-product structure was intended to reduce exposure to anti-abortion boycotts. The U.S. Food and Drug Administration approved the product as Mifeprex in 2000. Outside the United States, Hoechst transferred the medical-use rights to Exelgyn in 1997; the company was led by former Roussel Uclaf chief executive Édouard Sakiz and subsequently secured approvals in additional countries. Roussel Uclaf’s corporate independence ended through Hoechst’s consolidation strategy. Its agrochemical activities had been moved in 1994 to Hoechst Schering AgrEvo. Hoechst acquired the remaining Roussel Uclaf shares in early 1997, after which the pharmaceutical operations were integrated into Hoechst Marion Roussel. Hoechst Marion Roussel merged with Rhône-Poulenc in 1999 to form Aventis. Aventis merged with Sanofi-Synthélabo in 2004, and the combined company was later renamed Sanofi. The agrochemical succession developed separately: Hoechst Schering AgrEvo combined with Rhône-Poulenc’s agrochemical division to create Aventis CropScience, which Bayer acquired in 2002 and combined with its own agricultural-chemicals business. Roussel Uclaf therefore survives primarily as a historical predecessor within the corporate lineages of Sanofi and, for its agrochemical activities, Bayer CropScience.
- 2004
Aventis merges with Sanofi-Synthélabo
[1]The merger created Sanofi-Aventis, later renamed Sanofi, completing the principal pharmaceutical succession from Roussel Uclaf.
- 1999
Hoechst Marion Roussel becomes part of Aventis
[1]Hoechst Marion Roussel merged with Rhône-Poulenc to form Aventis.
- 1997
Absorption into Hoechst
[1]Hoechst acquired the remaining Roussel Uclaf shares and integrated its pharmaceutical operations into Hoechst Marion Roussel.
- 1994
Agrochemical operations transferred
[1]Roussel Uclaf’s agrochemical operations were transferred to Hoechst Schering AgrEvo.
- 1988
French authorization of mifepristone
[1]France authorized mifepristone used with a prostaglandin analogue for medical abortion.
- 1981
Initial clinical testing
[1]Medical-abortion testing was conducted in eleven women in Switzerland under the direction of Walter Herrmann, with support from consultant Étienne-Émile Baulieu.
- 1980
Synthesis of RU-486
[1]Georges Teutsch synthesized mifepristone, then designated RU-38486, during Roussel Uclaf research into glucocorticoid-receptor antagonists.
Products and positioning
A large French research-based pharmaceutical company with both medicines and agrochemical operations, later absorbed into the Hoechst and Sanofi corporate succession.
Medical-abortion medicine · 1988
Mifegyne
Mifegyne was Roussel Uclaf’s branded form of mifepristone. Used with a prostaglandin analogue, it became one of the company’s most important and politically contested products. It was first authorized in France in 1988, sold to French hospitals from 1990, and later approved in additional European markets. Roussel Uclaf eventually transferred rights outside the United States to Exelgyn after Hoechst completed its takeover.
Pharmaceutical development compound · 1980
RU-486
RU-486 was the development designation for mifepristone, synthesized at Roussel Uclaf in 1980. The compound was originally investigated as a glucocorticoid-receptor antagonist before its progesterone-antagonist properties led to development for medical abortion. The name became widely associated with the medicine even after commercial rights and branding moved to other organizations.
Agricultural chemicals
Agrochemical operations
Roussel Uclaf maintained an agrochemical business alongside its pharmaceutical activities. Those operations were separated from the pharmaceutical company in 1994 and transferred to Hoechst Schering AgrEvo. Their later corporate lineage ran through Aventis CropScience and Bayer CropScience rather than through the pharmaceutical business that became part of Sanofi.
Controversies
1997
Withdrawal of Roussel Uclaf’s direct mifepristone business
After Hoechst acquired the remaining shares, it announced the end of Roussel Uclaf’s manufacture and sale of Mifegyne and transferred non-U.S. medical-use rights to Exelgyn. The decision continued the long-running debate over corporate control and access to abortion medicines.
1988
Mifepristone distribution controversy
After anti-abortion protests and pressure associated with majority shareholder Hoechst AG, Roussel Uclaf’s board voted to stop distributing mifepristone shortly after French approval. The French government ordered distribution to resume, arguing that access to an approved medical product could not be withdrawn because of the abortion controversy.
Brand decisions
1997
Integration into HoechstM&ABackground
Hoechst had been Roussel Uclaf’s majority shareholder and acquired the remaining minority stake in early 1997.
Action taken
Hoechst ended Roussel Uclaf’s direct manufacture and sale of Mifegyne, transferred non-U.S. medical-use rights to Exelgyn, and combined the pharmaceutical operations into Hoechst Marion Roussel.
Aftermath
Roussel Uclaf ceased to operate as an independent pharmaceutical company. Its pharmaceutical business later became part of Aventis and then Sanofi.
1994
Transfer of U.S. medical-use rightsStrategyBackground
Roussel Uclaf faced continuing opposition and boycott threats connected with mifepristone in the United States.
Action taken
The company donated all U.S. rights for medical uses of mifepristone to the Population Council without remuneration.
Aftermath
The Population Council licensed the rights to Danco Laboratories, which later obtained U.S. approval for Mifeprex.
1988
Board vote to halt mifepristone distributionOtherBackground
Following French authorization, anti-abortion protests and concerns from Hoechst AG, which owned a majority of Roussel Uclaf, created pressure to withdraw the product.
Action taken
Executives and directors voted 16 to 4 to stop distribution, but the French government ordered the company to continue supplying the medicine two days later.
Aftermath
Mifepristone remained available in France and was subsequently sold to hospitals, while the episode established the product as a major public-health and political issue.
Recent events
- 2000
Mifepristone gains U.S. approval as Mifeprex[1]
Product launch · Regulation
Danco Laboratories, which had received rights through the Population Council, obtained U.S. Food and Drug Administration approval for mifepristone under the name Mifeprex.
- 1997
Hoechst acquires the remaining Roussel Uclaf shares[1]
M&A
Hoechst AG acquired the remaining minority interest in Roussel Uclaf and announced the end of its manufacture and sale of Mifegyne, while transferring non-U.S. medical-use rights to Exelgyn.
- 1994
U.S. medical-use rights for mifepristone transferred to the Population Council[1]
Other
Roussel Uclaf announced that it would give the Population Council the U.S. rights for medical uses of mifepristone without charging a remuneration. The Population Council later licensed the rights to Danco Laboratories.
- 1992
Mifepristone receives approval in Sweden[1]
Regulation · Product launch
Sweden approved mifepristone, adding another European market to the product’s distribution network.
- 1991
Mifepristone receives approval in Great Britain[1]
Regulation · Product launch
Mifepristone was approved in Great Britain, extending the European availability of Roussel Uclaf’s medical-abortion product.
- 1990
Mifegyne begins hospital sales in France[1]
Product launch · Pricing
Following a period in which the medicine was distributed free of charge in France, Roussel Uclaf began selling Mifegyne to French hospitals.
- 1988
France approves mifepristone for medical abortion[1]
Product launch · Regulation
After worldwide clinical trials involving approximately 20,000 women, Roussel Uclaf sought French authorization for mifepristone used with a prostaglandin analogue. Approval was announced in September 1988.
- 1982
Early medical-abortion results announced for RU-486[1]
Product launch · Other
Clinical testing in Switzerland involving eleven women produced successful early results for the use of mifepristone in medical abortion.
- 1980
Roussel Uclaf synthesizes the compound later known as mifepristone[1]
Product launch · Other
Chemist Georges Teutsch synthesized RU-38486 during a Roussel Uclaf research program on glucocorticoid-receptor antagonists. The compound was later recognized as a progesterone antagonist and became known as RU-486.
Sources2 sources
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