Used primarily in the treatment of respiratory tract infections such as bronchitis and pneumonia, especially those caused by susceptible bacteria like *Mycoplasma pneumoniae* and *Haemophilus influenzae*. It is effective due to its long half-life, allowing for once-daily dosing, which improves patient compliance. Also used in managing skin and soft tissue infections. Its active metabolite, erythromycylamine, provides sustained antibacterial activity. Often prescribed when patients are intolerant to penicillin.