Block Drug Company was a pharmaceutical company based in Jersey City, New Jersey, United States, that specialized in dental care products. Its most popular products included Polident denture cleanser, Poli-Grip denture adhesive, Dentu-Creme denture toothpaste, Nytol sleeping pill, Tegrin medicated shampoo for psoriasis, Lava hand soaps (acquired from Procter & Gamble), Beano and Phazyme anti-gas products, Balmex diaper rash ointments, and Sensodyne desensitizing toothpaste.
GlaxoSmithKline purchased the company for $1.24 billion in 2001.
The company was founded in 1907 by Alexander Block, a Russian immigrant who had a small drugstore on Fulton Street in Brooklyn, New York. He turned the company into a wholesaler in 1915, then became a drug manufacturer in 1925, acquiring a 50 percent interest in Wernet's Dental Manufacturing Company.
Block Drug moved its headquarters to Jersey City, New Jersey in 1938.
Although Alexander Block built the company largely through acquisitions, he developed the Polident brand internally during the 1930s. In 1948, Block Drug rolled out the Ammi-i-Dent tooth powder, and in the early 1950s, the company developed Nytol. After Alexander Block's death in 1953, his son Leonard N. Block (1911–2005) took over, eventually becoming the company's chairman. The last major new product the company introduced was Tegrin, in 1964.
Although Block Drug was a public company from 1971 until 2001, it operated much like a private, family-run firm, with the Block family holding all voting shares plus 54 percent of the non-voting stock. In addition, the company never held annual meetings or issued proxy statements
Leonard N. Block died in 2005 at age 93 after suffering for years from Alzheimer's disease. Block's nephew John P. Roberts was the producer of the Woodstock Festival using money from his Block inheritance.