The British Drug Houses (BDH) was founded in 1908 as a wholesaler for private chemists by the amalgamation of various old established London firms of manufacturing chemists and wholesale druggists : Barron, Harveys & Co.; Hodgkinsons, Clarke & Wood; Herron, Squire & Francis; Davy, Hill & Co. and A. S. Hill & Son.
In 1909 new works were built in Grantham Street, London N1, which were sufficiently large to accommodate the existing businesses.
The company expanded, opening new factories in Poole (1946) and Godalming (1952), and acquiring several wholesale and manufacturing chemists.
In 1964 the main business of the company became laboratory reagents and chemicals.
The company name was changed to BDH Chemicals in 1967. In 1973 it was acquired by E. Merck of Germany and the BDH name was retained as a brand name.