The memory enhancing effects of a Ginkgo biloba/Panax ginseng combination in healthy middle-aged volunteers

Psychopharmacology (Berl). 2000 Nov;152(4):353-61. doi: 10.1007/s002130000533.


The effects of capsules containing 60 mg of a standardised extract of Ginkgo biloba (GK501) and 100 mg of a standardised extract of Panax ginseng (G115) on various aspects of cognitive function were assessed in healthy middle-aged volunteers. A double blind, placebo controlled, 14 week, parallel group, repeated assessment, multi-centre trial of two dosing regimens, 160 mg b.i.d. and 320 mg o.d. was conducted. Two hundred and fifty-six healthy middle-aged volunteers successfully completed the study. On various study days (weeks 0, 4, 8, 12 and 14) the volunteers performed a selection of tests of attention and memory from the Cognitive Drug Research computerised cognitive assessment system prior to morning dosing and again, at 1, 3 and 6 h later. The volunteers also completed questionnaires about mood states, quality of life and sleep quality. The Ginkgo/ginseng combination was found significantly to improve an Index of Memory Quality, supporting a previous finding with the compound. This effect represented an average improvement of 7.5% and reflected improvements to a number of different aspects of memory, including working and long-term memory. This enhancement to memory was seen throughout the 12-week dosing period and also after a 2-week washout. This represents the first substantial demonstration of improvements to the memory of healthy middle-aged volunteers produced by a phytopharmaceutical.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Cognition / drug effects
  • Double-Blind Method
  • Drug Interactions
  • Female
  • Ginkgo biloba / chemistry*
  • Humans
  • Male
  • Memory / drug effects*
  • Middle Aged
  • Outcome Assessment, Health Care
  • Panax / chemistry*
  • Plant Extracts / pharmacology
  • Plants, Medicinal*
  • Surveys and Questionnaires


  • Plant Extracts