Ampicillin is bactericidal broad spectrum semi-synthetic Penicillin , It is active against G +ve and G -ve bacteria It produces its bactericidal effect by inhibiting the cell wall synthesis in the later stage by inhibiting the attachment of the glycine chains to the short peptides. Ampicillin is bactericidal antibiotic,. It is active against G+ve and G – Ve organisms including species of corynebacterium, clostri duim, E. coli, klebsiella, higella, jalmorella, for teus, brucella nad pastcurella spp.