DEXTRO PROPOXYPHENE HYDROCHLORIDE (Darvon) is a well-known synthetic, nonantipyretic, orally effective analgesic compound which was introduced into therapeutics as a substitute for codeine in 1957.1Since that time, and in spite of its rather widespread use, no documented cases of dextro propoxyphene addiction have appeared. Thus the early studies2-4suggesting that this drug has few addictive qualities seem to have been verified by the general clinical use of the drug. Nevertheless, although not widely appreciated, it is a fact that dextro propoxyphene hydrochloride can partially suppress the morphine abstinence syndrome in both monkeys5and man.6Therefore, a potential habituation to, or physical dependence syndrome on, this agent should be suspected in any case of excessive use of this drug. It is the purpose of this communication to report our experience with one patient psychically dependent on dextro propoxyphene hydrochloride who showed some evidence of tolerance and