7-[.alpha.-(2-Aminomethyl-1-cyclohexyl)-acetamido]-3-heterocyclic thiomethyl-3-cephem-4-carboxylic acids, and their nontoxic, pharmaceutically acceptable salts and their Schiff bases, as made by reaction of salicylaldehyde with the free amino group, are valuable as antibacterial agents and are particularly valuable as therapeutic agents in poultry and animals, including man, in the treatment of infectious diseases caused by many Gram-positive and Gram-negative bacteria.