By a short-term combined prophylactic-therapeutic procedure, the following compounds were found to be active against staphylococcal infections in Swiss mice: gamma-aminobutyric acid, gamma-amino-beta-hydroxybutyric acid (GABOB), delta-amino-valeric acid (DAVA), epsilon-aminocaproic acid (EACA), trans-4-aminomethylcyclohexanecarboxylic acid (trans-AMCHA), taurine, and cysteic acid. Many of these compounds had displayed limited or no activity by a previously used prophylactic procedure. Although DAVA and GABOB were the most potent of the straight-chain omega-amino acids, trans-AMCHA displayed the greatest antistaphylococcic activity of the omega-amino acids thus far investigated. Homocarnosine (gamma-aminobutyrl histidine, which also was active by the prophylactic procedure) equalled trans-AMCHA in activity. Taurine was similar in potency to DAVA, and the activity of cysteic acid approximated that of EACA.