Pine (Pinus species), particularly pine needles, resin, and bark, has a long history of use in traditional medicine systems, including Traditional Chinese Medicine (TCM), Russian folk medicine, and various Native American practices. In TCM, pine is sometimes included in remedies for respiratory complaints, including coughs, bronchitis, and conditions characterized by "phlegm" or fluid accumulation in the lungs. This use is based on the aromatic, expectorant, and mildly antiseptic qualities attributed to pine oils and extracts. The volatile oils, such as pinene, are thought to stimulate the respiratory tract and help clear mucus.

However, robust scientific studies specifically examining pine’s efficacy in treating fluid accumulation in the lungs (such as pulmonary edema or pleural effusion) are lacking. Most modern research on pine has focused on its antimicrobial, antioxidant, and anti-inflammatory properties, with limited direct application to serious lung conditions involving fluid. Some laboratory studies suggest that pine extracts may have bronchodilatory and mucolytic effects, which could theoretically support traditional uses for mild respiratory congestion or cough, but not for significant fluid buildup.

In summary, pine’s use for supporting the lungs (especially in the context of fluid) is rooted primarily in traditional medicine practices, with limited scientific validation and mostly indirect evidence for its effects on respiratory health.