+**Sputum** is mucus expectorated from the respiratory tract, a visible sign of the body's internal state. Its character offers clues for [Medical Diagnosis](/wiki/medical_diagnosis), often pointing to conditions like [Lung Disease](/wiki/lung_disease).
+## See also
+- [Mucus](/wiki/mucus)
+- [Cough](/wiki/cough)
+- [Respiration](/wiki/respiration)
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