Used primarily to treat bacterial infections such as bronchitis and pneumonia, especially those caused by susceptible strains of bacteria including *Chlamydia pneumoniae* and *Mycoplasma pneumoniae*. It is effective in cases where other antibiotics may not work well due to its broad-spectrum activity. Due to risk of photosensitivity, its use is often limited or requires strict sun avoidance during treatment. It is taken orally and achieves good tissue penetration, making it suitable for respiratory tract infections.