Kempthorne Prosser & Co. Ltd, also known as the New Zealand Drug Company Ltd, was the leading drug and fertiliser manufacturer in New Zealand from 1869 until 1978. The company's full name was Kempthorne Prosser & Co.'s New Zealand Drug Co. Ltd, established in Dunedin.
Thomas Whitelock Kempthorne and Evan Prosser entered into business together in 1870 as chemists.[1] They set up Kempthorne Prosser, which became a limited liability company in 1879. The head office was set up on Stafford Street in City Rise, Dunedin. In 1904 Thomas Whitelock Kempthorne retired. Kempthorne Prosser & Co became Kempthorne Prosser & Co. Ltd in 1879 when the New Zealand Drug Company was formed.