Schering-Plough Corporation is a pharmaceutical company founded in 1851 by Ernst Christian Friedrich Schering as Schering AG in Germany. In 1971, the Schering Corporation merged with Plough (founded by Memphis area entrepreneur Abe Plough in 1908) to form Schering Plough.

In March 2007, Schering-Plough Corp. purchased Organon International, the pharmaceutical manufacturing unit of Netherlands-based Akzo Nobel, for $14.4 billion, giving the US pharmaceutical company an array of women’s health products and numerous late-stage pipelines of experimental medicines.

In March 2009, Merck & Co. (aka. Merck, Sharpe & Dohme, MSD) proposed to merge with Schering-Plough in a $41 billion deal. This combined corporation would be the 2nd largest pharmaceutical company in the world. The proposed deal is expected to close in the fourth quarter of 2009.

The Company has 4 manufacturing operations in Ireland:

Schering-Plough Bray (Manufacture of Veterinary Products) – In April 2009, it was announced that the Bray plant was to close with the loss of 240 jobs – the plant is expected to close by mid 2011.

Schering-Plough Avondale (Manufacture of Active Pharmaceutical Ingredients, API’s), employs approximately 380 people and produces up to thirty active pharmaceutical products using multi-step synthesis, and is a strategic site worldwide in the parent company’s production operations. The most important product currently manufactured in Avondale is Loratadine, the active ingredient of Clarityn (Schering-Plough’s Hay fever Blockbuster).

Schering-Plough Brinny (Manufacture of Biopharmaceuticals) – The Brinny plant is Schering-Plough’s centre of excellence for the manufacture and quality assurance of its biopharmaceutical products. The main product for world-wide distribution is INTRON A (Interferon A) - used to treat various cancers (e.g., leukemia, melanoma, AIDS-related Kaposi’s sarcoma). It is also used to treat virus infections (e.g., chronic hepatitis B, chronic hepatitis C, condylomata acuminata).They also produce other biotechnology products for commercial use and development/clinical trials.

Organon Ireland (Manufacture of Gynaecological Pharmaceuticals) – Organon was incorporated into Schering Plough in 2007 and employs 650 people in Ireland in Swords, Co Dublin. The site employs the latest manufacturing technology and processes to make a range of family planning products and a treatment for infertility. The final products are packaged for over 50 countries worldwide.