Excerpted from Bensky:  Chinese Herbal Medicine Materia Medica, 3rd ed.

• Aromatically transforms dampness, awakens the Spleen, and regulates the middle:  for dampness obstructing the middle burner with such symptoms as stifling sensation in the chest, lack of appetite, nausea, and an white, moist tongue coating.  Because it is a neutral herb that does not cause dryness, it can also be used for damp-heat in the Spleen channel with a sweet, sticky taste in the mouth, excessive saliva, and bad breath.*
• Transforms dampness and releases summerheat:  for exterior summerheat-dampness patterns with nausea.  Also for the early stages of damp-warmth.*
• Aromatically dispels middle burner turbid filth to unbind the Stomach:  for internal accumulation of increasingly thickened dampness in the middle burner binding Stomach qi, leading to symptoms such as lethargy, nausea, loss of appetite, epigastric and abdominal distention and pain, and particularly a thick and greasy tongue coating.  This pathology can combine with either damp-heat or cold-dampness.  Usually combined with Pogostemonis/Agastaches Herba (huo xiang) for this purpose.*

Pei Lan - Eupatorium fortunei