Mezlocillin Sodium is primarily used as an antibiotic in the treatment of various bacterial infections. It is effective against a wide range of Gram-negative and some Gram-positive bacteria, making it useful in treating infections such as urinary tract infections, respiratory tract infections, septicemia, and intra-abdominal infections. It is often administered in hospital settings for severe infections, particularly when the causative bacteria are resistant to other antibiotics. Additionally, it is used in combination with other antibiotics to enhance its efficacy in treating complex or multi-drug resistant infections. Its broad-spectrum activity and ability to penetrate tissues make it a valuable option in managing serious infections.