It is a semi-synthetic broad-spectrum penicillin antibiotic that mainly acts on the bacterial reproduction stage by inhibiting the biosynthesis of cell wall mucopolypeptides. It is effective against many Gram-positive and Gram-negative bacteria.

It has a β-lactam structure similar to penicillin and has only weak antibacterial activity itself, but it can inactivate enzymes produced by many bacteria by blocking the active site of β-lactamase, especially for clinically important plasmid-mediated β-lactamase. It can protect amoxicillin from hydrolysis and destruction by β-lactamase, so it is still effective against resistant bacteria that produce β-lactamase.

Ampicillin sodium is a broad-spectrum semi-synthetic penicillin. This product has a strong antibacterial effect on hemolytic streptococci, Streptococcus pneumoniae and non-penicillinase-producing Staphylococci, which is similar to or slightly inferior to penicillin. Ampicillin also has a good antibacterial effect on viridans streptococci, and is better than penicillin on enterococci and Listeria. This product has antibacterial activity against Corynebacterium diphtheriae, Bacillus anthracis, Actinomyces, Haemophilus influenzae, Bordetella pertussis, Neisseria and anaerobic bacteria except Bacteroides fragilis. Some Proteus mirabilis, Escherichia coli, Salmonella and Shigella are sensitive to this product. Ampicillin exerts its bactericidal effect by inhibiting bacterial cell wall synthesis.

Ampicillin sodium is a broad-spectrum semi-synthetic penicillin. This product has a strong antibacterial effect on hemolytic streptococci, Streptococcus pneumoniae and non-penicillinase-producing Staphylococci, which is similar to or slightly inferior to penicillin. Ampicillin also has a good antibacterial effect on viridans streptococci, and is better than penicillin on enterococci and Listeria. This product has antibacterial activity against Corynebacterium diphtheriae, Bacillus anthracis, Actinomyces, Haemophilus influenzae, Bordetella pertussis, Neisseria and anaerobic bacteria except Bacteroides fragilis. Some Proteus mirabilis, Escherichia coli, Salmonella and Shigella are sensitive to this product. Ampicillin exerts its bactericidal effect by inhibiting bacterial cell wall synthesis.

This product is an acid-resistant and penicillinase-resistant penicillin, which has good antibacterial activity against penicillinase-producing Staphylococci, but its antibacterial activity against various streptococci and non-penicillinase-producing Staphylococci is inferior to penicillin G. This product exerts its bactericidal effect by inhibiting bacterial cell wall synthesis.

Broad-spectrum semi-synthetic penicillin has antibacterial effects on hemolytic streptococci, viridans streptococci, pneumococci, penicillin G-sensitive Staphylococcus aureus, gonococci, Haemophilus influenzae, enterococci, Salmonella, Salmonella typhi and Proteus. It has no effect on Staphylococcus aureus that produces penicillinase. Bacteria have complete cross-resistance to this product and ampicillin.