A moderate-spectrum, bacteriolytic beta-lactam antibiotic C₁₆H₁₉N₃O₅S closely related to ampicillin and with similar properties, but more readily absorbed when taken orally. It is used to treat bacterial infections caused by susceptible microorganisms.
An aminoglycoside and bactericidal antibiotic C₂₁H₃₉N₇O₁₂ that is produced by a soil actinomycete (Streptomyces griseus), is active against many bacteria, and is administered via intramuscular injection especially in the treatment of infections by gram-negative bacteria. It was the first drug to be successful against tuberculosis but is now chiefly used with other drugs because of its toxic side effects.