The therapeutic effectiveness of benzoyloxymethyl-thiamin in controlling post-operative pain in odontostomatological surgery has been examined. The double blind study used a placebo and concerned 100 patients subjected to avulsion of the third molar in dysodontiasis on an out-patient basis. The results point to the effectiveness of benzoyloxymethyl-thiamin in the symptomatic treatment of post-operative pain symptomatology both as regards its duration and intensity; the drug also proved to be very well tolerated and its administration was not accompanied by any unwanted side-effects.