How is Legionnaires' disease treated?

Legionnaires' disease is a serious form of pneumonia treated with antibiotics. The specific antibiotic and treatment approach depend on the severity of your illness, your overall health, and how quickly the infection is diagnosed.

Common antibiotics used to treat Legionnaires' disease include:

• Fluoroquinolones (such as levofloxacin or moxifloxacin)
• Macrolides (such as azithromycin)

Treatment typically involves:

• Mild to moderate cases: Oral antibiotics for 5–10 days
• Severe cases: IV antibiotics in a hospital setting, often for 7–21 days
• Supportive care: Oxygen therapy, IV fluids, and monitoring for complications

Early treatment is critical. Delayed antibiotics can lead to respiratory failure, septic shock, or death, especially in older adults, smokers, or those with weakened immune systems.

Because Legionnaires' disease shares symptoms with many other respiratory illnesses—like COVID-19, the flu, or common pneumonia—it's important to identify possible causes quickly so you can seek the right care. A free, instant, online symptom check can help you understand what your symptoms may mean and guide your next steps, whether that's calling your doctor, visiting urgent care, or going to the ER. Taking a few minutes now could help you get the right treatment faster—and potentially save your life.

Reviewed for medical accuracy: 07/20/2026