Before the invention of modern antibiotics and antiseptics, physicians experimented with mercury-containing compounds to try to stave off microbial pathogens. Thimerosal was born of those efforts. Dr. Morris Kharasch, a university chemist and Eli Lilly fellow, developed thimerosal and filed for a patent in June, 1929, describing thimerosal as an “alkyl mercuric sulfur compound” with antibacterial properties.