1. 1. A general review is given of the conflicting opinions concerning the relationship between ascorbic acid and allergic conditions in human beings. A discussion of the rationale of ascorbic acid therapy is presented. 2. 2. The results of an experiment are recorded in which eight young, male adults with hay fever acted as subjects. At various intervals, a total of forty-three control skin tests were made on these subjects with an extract of short ragweed. The plasma levels of ascorbic acid were measured at the time of most skin testing. Then at various intervals large amounts of ascorbic acid were given over a period of several days and, after taking the vitamin, a total of forty-four more skin tests were made on the same eight subjects. The plasma level of ascorbic acid was likewise measured as previously. The average diameters of the erythemas of the two sets of data were compared. 3. 3. The conclusion reached was that by the methods used in this experiment there is no evidence that ascorbic acid has any significant effect upon allergic skin reactions due to intracutaneous injection of an extract of short ragweed pollen, although it is realized that this experiment, in itself, cannot entirely prove that ascorbic acid can have no clinical value.