In 1945, Cheplin Laboratories was renamed Bristol Laboratories and Frederic N. Schwartz was put in charge. Bristol-Myers bought Cheplin Laboratories in 1943ﾗa Syracuse, New York, manufacturer of acidophilus milkﾗand broke ground for a new penicillin plant.

Cheplin became a key supplier of penicillin for the Allied armed forces during World War II. After the war it was clear that penicillin and other antibiotics were an immense opportunity for Bristol-Myers.