What does it mean when there is blood in the phlegm during a cold?

The common cold is a relatively prevalent illness; most individuals can effectively manage and treat it once symptoms appear. Only a small proportion of patients develop severe complications—such as blood-tinged sputum, which may indicate worsening of the cold. So, what causes blood in sputum during a cold? Below, we address this question.

What Causes Blood in Sputum During a Cold?

1. Mucosal Injury

During a cold, particularly with severe coughing, minor trauma to the pharyngeal mucosa may occur, resulting in small amounts of blood mixed in the sputum. This is often attributable to excessive force during coughing, causing rupture of superficial blood vessels. In most cases, this symptom resolves spontaneously as other cold symptoms improve. Patients are advised to adopt the most comfortable position—either prone or supine—but with the head turned to one side to prevent aspiration of blood into the airway, which could lead to asphyxiation.

2. Pulmonary Tuberculosis

Hemoptysis (blood in sputum) manifests in various forms: streaks of bright red blood commonly occur in pulmonary tuberculosis or bronchiectasis; blackish blood-tinged sputum is frequently associated with pulmonary infarction; and frothy, blood-tinged sputum suggests pulmonary edema. In wind-heat type colds, blood-tinged sputum may also appear, accompanied by symptoms such as sore, red, swollen throat and coughing—requiring treatment with traditional Chinese herbal medicines that dispel wind and clear heat. Additionally, conditions like bronchiectasis may worsen during colds, exacerbating cough and sputum production and potentially leading to hemoptysis. Therefore, individuals with chronic respiratory diseases—especially long-term smokers—are advised to seek comprehensive medical evaluation at a hospital.

3. Lung Abscess

Diseases such as pulmonary tuberculosis, pneumonia, and lung abscess typically present with symptoms including throat itchiness, chest tightness, and cough producing blood-tinged sputum. Prompt management of hemoptysis is essential, and patients should undergo thorough clinical evaluation to identify the underlying cause. Yunnan Baiyao—a traditional Chinese medicine—possesses properties that promote blood stasis resolution and hemostasis and is effective for treating hemoptysis. Concurrently, supportive therapies—including intravenous fluid resuscitation, blood transfusion, anti-shock measures, and antibiotics—should be administered. Close monitoring of disease progression is critical; if bleeding remains uncontrolled, alternative interventions must be considered.

The above outlines potential causes of blood-tinged sputum during a cold. We hope this information is helpful to you.