<Li> Pink to red / bloody: Traumatic tap, malignancy, pulmonary infarction, intestinal infarction, pancreatitis, trauma . </Li> <Li> Green - white, turbid: Rheumatoid arthritis with pleural effusion . </Li> <Li> Green - brown: Biliary disease, bowel perforation with ascites . </Li> <Li> Milky - white or yellow and bloody: Chylous effusion . </Li>

Abnormal fluid in the pleural cavity between the visceral and parietal pleura is a