Diphenan is p-benzyl-phenyl-carbamate. Various workers have reported that diphenan will rid children of oxyurids and it has been claimed to be nontoxic and tasteless and to have the advantage of being a vermicide as opposed to a vermifuge. An attempt has been made to assess the efficacy of diphenan as a vermicide. Diphenan was given far in excess of the normal dosage. Subsequent examnation showed few cures and these mostly in lightly infested children. The condition of many was unchanged and that of some worse after treatment. No toxic reactions were encountered. Moreover, diphenan was found to have no detectable anthelmintic effect when given in high dosage in the treatment of enterobiasis.