As an intestinal bacterial metabolite of ginseng protopanaxadiol saponins, ginsenoside compound K (20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol, CK) is a major deglycosylated metabolite form of ginsenosides which is absorbed into the systemic circulation. And it has demonstrated such diverse intriguing biological properties as anticarcinogenic, anti-inflammation, antiallergic, anti-diabetic, anti-angiogenesis, anti-aging, neuroprotective and hepatoprotective effects. The present review shall summarize recent studies on various biotransformation and pharmacological activities of CK. Copyright © 2014. Published by Elsevier B.V.