Murine caspase-11 is orthologus to human caspase-4 and caspase-5, and is required for the response to cholera toxin B and infection with Escherichia coli, Citrobacter rodentium or Vibrio cholerae. Caspase-11 rather than caspase-1 is the main offender involved in sepsis. Hence, caspase-11 plays an essential pro-inflammatory role in innate immune response to bacterial infections.