ObjectiveOrdinarily, a diuretic uniformly performs diuresis of body water and decreases it. When a diuretic is used for gestational edema, blood vessel dehydration and amniotic fluid are expected to decrease. This may be rather harmful for the gestational prognosis. Goreisan's mechanism of efficacy is different from that of ordinary diuretics. The results of treating gestational edema and amniotic fluid reduction with goreisan were studied. Whether goreisan is helpful for improving gestational prognosis was studied.Clinical resultsGoreisan is effective in the treatment of gestational edema. During edematous treatment, goreisan exhibits a diuretic effect. After edema has improved, goreisan does not exhibit a compulsory diuresis effect. These effects were ascertained by examining the change in the expectant mother's weight. Goreisan appeared to normalize the gross body water volume. In the presence of edema, a reduction in the amniotic fluid volume was often apparent after 36 weeks of gestation. Treatment of gestational edema by goreisan prevented the reduction of the amniotic fluid volume. Maximum vertical pocket (MVP) changes before and after treatment with goreisan for oligohydramnios were studied. Goreisan prospectively appeared to exhibit a therapeutic effect on oligohydramnios.ConclusionGoreisan contributes to improvement in the prognosis of the course of gestation. Goreisan, rather than diuretics, corrects the maldistribution of body water. Only Kampo medicine has these activities for water metabolism. Ordinary diuretics cannot be substituted for these medicines.