The drug is used for treatment of infectious diseases such as community acquired pneumonia, exacerbation of chronic bronchitis, acute sinusitis, pharyngitis and skin infections. The active ingredient in Omnicef is cefdinir—a semi-synthetic cephalosporin broad-spectrum antibiotic of the third generation for oral administration. Like other cephalosporin antibiotics, cefdinir has a bactericidal action against susceptible organisms through the inhibition of synthesis of bacteria peptidoglycan cell walls by interfering with the final stage of transamination, required for cross-linking.