PURPOSE: An analgesic having low toxicity, comprising [6]-shogaol or [6]-gingerol, an extract from a ginger as an active ingredient.

CONSTITUTION: A compound shown by the formula I (R is a group shown by the formula II or III) as an active ingredient is pharmaceutically manufactured into an injection, powder, tablet, etc. for use. The compound shown by the formula I can be obtained by extracting the rhizome of a ginger, a zingiberaceous plant with an ether, etc. to give an essence, fractionating it by column chromatography, followed by subjecting each fraction to thin layer chromatography so that it is separated. In case of oral administration, a dose is 70W500mg [6]-shogaol (a compound shown by the formula I where R is a group shown by the formula II) or about 140W200mg [6]-gingerol (a compound shown by the formula I where R is a group shown by the formula III).