Dang Shen use
Dang Shen is very similar to Ren Shen (ginseng). The differences are:
Ren Shen-
1. rescues collapsed qi
2. tonifies Spleen qi
3. tonifies Lung qi
4. generates fluids
5. calms shen (spirit)
Dang Shen only does 2, 3, and 4 of the above.
Generally speaking, you can substitute dang shen for ren shen in most formulas (usually done because dang shen is cheaper), but you must increase the dosage. Also keep in mind that there are several varieties of ren shen, and the different varieties have slightly different properties. Also, many times dang shen is considered more appropriate for younger people.
What are you thinking of using dang shen for?
Jack
"Do not follow in the footsteps of the men of old, seek what they sought"