Exhibit 99.1 FOR IMMEDIATE RELEASE Investor Contact: Kathryn Grissom (317) 273-9284 or kathryn.grissom@elancoah.com Media Contact: Colleen Parr Dekker (317) 989-7011 or colleen.dekker@elancoah.com Elanco Animal Health Reports Fourth Quarter and Full Year 2023 Results • Fourth Quarter 2023 Financial Results: ◦ Revenue of $1,035 million ◦ Reported Net Loss of$141 million, Adjusted Net Income of $39 million ◦ Adjusted EBITDA of$165 million or 15.9% of Revenue ◦ Reported EPS of $(0.29), Adjusted EPS of$0.08 ...