Although ginseng has been shown to have an antiobesity effect, antiobesity-related mechanisms are complex and have not been completely elucidated. In the present study, we evaluated ginseng's effects on food intake, the digestion, and absorption systems, as well as liver, adipose tissue, and skeletal muscle in order to identify the mechanisms involved. A review of previous in vitro and in vivo studies revealed that ginseng and ginsenosides can increase energy expenditure by stimulating the adenosine monophosphate-activated kinase pathway and can reduce energy intake. Moreover, in high fat diet-induced obese and diabetic individuals, ginseng has shown a two-way adjustment effect on adipogenesis. Nevertheless, most of the previous studies into antiobesity effects of ginseng have been animal based, and there is a paucity of evidence supporting the suggestion that ginseng can exert an antiobesity effect in humans.