Clear is the normal state of your phlegm, but if you're coughing up clear phlegm, chances are you have some sort of irritant in your respiratory tract. Allergies are a common cause of this type of phlegm. Other causes include viral pneumonia and viral bronchitis. Your doctor can determine whether it is allergies or something more serious.

This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.