Penicillin V potassium tablets are penicillin antibiotics, the antibacterial spectrum is the same as penicillin, with antibacterial activity against most gram-positive bacteria, gram-negative bacteria, and individual gram-negative bacilli, such as haemophilus, spirochetes, and radiolucent bacteria. However, penicillin V potassium tablets have no antibacterial activity against most staphylococci, including Staphylococcus aureus and coagulase-negative staphylococci, which can produce beta-endosulfanilamide molds to inactivate the hydrolysis of the product, so penicillin V potassium tablets do not have antibacterial activity against most staphylococcal strains. The mechanism of action of penicillin V potassium tablets is that it inhibits the cell wall synthesis of bacteria, causing rapid rupture and lysis of bacteria. Penicillin V potassium tablets are contraindicated in patients with positive reaction to penicillin skin test, allergy to penicillin and other penicillins, and infectious mononucleosis. Penicillin V potassium tablets can treat tonsillitis, pharyngitis, scarlet fever, dengue, pneumonia, bronchitis, sinusitis, otitis media, skin and soft tissue infections, infective endocarditis and other diseases.