Cephalexin is an antibiotic belonging to the cephalosporin class, used to treat a variety of bacterial infections. It works by inhibiting the synthesis of bacterial cell walls, leading to cell rupture and death. Cephalexin is particularly effective against gram-positive bacteria, including Streptococcus and Staphylococcus, making it useful for treating skin infections, respiratory tract infections, urinary tract infections, and bone infections. Administered orally, cephalexin is well-absorbed and generally safe, with a favorable side effect profile. It is commonly prescribed in 250mg to 500mg doses, and patients are advised to complete the full course to prevent resistance and ensure effective treatment.