Louis Wendlin Sauer (August 13, 1885 – February 10, 1980) was an American pediatrician who became known for perfecting the vaccine used to prevent pertussis (whooping cough), saving countless lives around the world.

He married Lucia Mira Seypelt on August 20, 1912 in Berlin, while attending school there.

He graduated from Rush Medical College in 1913 and began working in pediatrics.

Dr. Sauer never asked for compensation for developing vaccines and told an interviewer later, "One doesn't do that thing for money.

"[3] Dr. Sauer was a professor at the Northwestern University Medical School in Evanston, Illinois, until his retirement in 1959 to Coral Gables, Florida.