The finding of abnormal estrogenic activity coupled with thiamine deficiency in cases of menorrhagia and uterine cancer suggests a possible etiological correlation between the dietary deficiency, the abnormal estrogen level, and the pathological lesion. The specific element deficient in these cases was thiamine, while the other B factors were normal. Preliminary report of the evidence is made in this small series while more extensive studies on a large series of cases are being pursued. Cornification in cytology smears was used to study estrogenic activity, since the present study was prompted by cytological findings; the method is simple, practical, and reasonably accurate. The urinary estimation measures only the amount excreted, and if liver impairment actually is present, the quantity excreted would not give a true index of the amount retained in the body. Further studies are being undertaken in which estrogenic, urinary, and cornification levels are being compared before and after thiamine administration in cases proven to be deficient.