PURPOSE: To provide the titled external drug containing allithiamine as an active component, directly absorbable through the skin of the diseased part, effective in remarkably increasing and keeping the vitamin B1 concentration at the diseased part and exhibiting excellent effect for the remedy of neuralgia, myalgia, lumbago, etc., and the mitigation of the pain of the diseases.

CONSTITUTION: The objective agent contains an allithiamine which is a disulfide- type vitamin derivative such as thiamine allyl disulfide or thiamine tetrahydrofurfuryl disulfide. The active component can be directly absorbed to the diseased part by coating or applying the external agent (e.g. ointment or poultice) to the skin of the diseased part. The B1 concentration can be maintained solely at the diseased part without increasing the concentration in the whole body by controlling the rate of absorption of allithiamine from the drug. Accordingly, the remedying effect can be extremely safely promoted.