The high street chain, Boots, could be under new ownership by 2015.
The largest drug store chain in the US, Walgreens, has signed a £4.3bn deal to take a 45% stake in Alliance Boots, the parent company of Boots.
Walgreens, which also trades as Duane Reade, said the partnership will create the first global pharmacy business, with 11,000 stores in 12 countries.
The deal will cement Walgreen’s position as the world’s biggest pharmacy chain.
Neil Saunders, a retail analyst at Conlumino said the merger will bring savings to both companies.