OBJECTIVETo elucidate that rhubarb extract as a purgative should be delivered to colon from a pharmaceutical point of view.

METHODEffects of anthranoids and free anthraquinones as purgatives on the colon motility and transit time, the absorption in vivo, and the loss in the processes of extraction, concentration and dryness were reviewed, based on the recent 60 years pharmacological, pharmaceutical and clinical experimental studies at home and abroad.

RESULT AND CONCLUSIONFree anthraquinones in rhubarb extract should be regarded as purgative principles. Close attention should be paid to the loss of free anthraquinones not only in the processes of extraction, concentration and dryness, but also in the process of transit in the upper gastrointestinal tract. Colon-targeting delivery of rhubarb extract, as a purgative, may prevent absorption of free anthraquinones in the upper gastrointestinal tract, thus improving clinical effects and lowering dosage.