Cephalosporins are β-lactam antibiotics derived from cephalosporin C obtained from Cephalosporium acremonium. They act by inhibiting bacterial cell wall synthesis through binding to penicillin-binding proteins. Cephalosporins are classified into generations according to their antimicrobial spectrum and resistance to β-lactamases. First generation cephalosporins are mainly active against gram-positive organisms such as Streptococcus and Staphylococcus. Their activity against gram-negative bacteria is limited. Common drugs are cephalexin, cefadroxil, cefazolin and cephradine. These drugs are effective against organisms like Proteus mirabilis, Escherichia coli and Klebsiella pneumoniae. Therapeutically, they are used in skin and soft tissue infections, streptococcal pharyngitis, urinary tract infections and surgical prophylaxis. Cefazolin is widely used before surgery to prevent postoperative infections because of its good tissue penetration and long duration of action. Second generation cephalosporins have greater gram-negative activity while retaining moderate