Ginseng, particularly Panax ginseng and Panax quinquefolius (American ginseng), has been traditionally used in East Asian medicine to support overall vitality, stress adaptation, and balance within the body. From a scientific standpoint, several studies suggest that ginseng may influence the autonomic nervous system, including modulation of the parasympathetic nervous system (PNS). Experimental research indicates that ginsenosides, the active compounds in ginseng, can promote parasympathetic activity by enhancing acetylcholine release and affecting muscarinic receptors. Animal and limited human studies have shown that ginseng can reduce heart rate and increase heart rate variability, which are markers of parasympathetic tone and vagal activity.

However, the depth and quality of clinical evidence are moderate. Many studies are small, short-term, or lack robust controls. Meta-analyses and systematic reviews often conclude that while there is some support for ginseng's ability to modulate stress responses and autonomic balance, more rigorous human trials are needed. Overall, the evidence is stronger than for many traditional herbs, but it does not reach the highest level of scientific validation. Thus, the use of ginseng to support the parasympathetic nervous system is scientifically plausible and modestly supported, but not definitively proven.