The combination of procaine penicillin G and neomycin acts additive and in some cases
synergistic. Procaine penicillin G is a narrowspectrum penicillin with bactericidal action
against mainly Grampositive bacteria. It acts by inhibition of bacterial cell wall synthesisin
actively growing bacteria. Neomycin is an aminoglycoside with bactericidal action against
mainly Gram-negative bacteria. Its action is based on inhibition of bacterial protein synthesis.