Counter current transfer of many substances, including steroids and peptide hormones, takes place from the veins and lymph vessels to the arterial blood in the female adnexa. The vascular system to the ovaries, tubes, uterus, and vagina is involved, and transfer from one organ to another is possible due to the anatomy and physiology of the vessels. Examples of physiological importance are given: regulation of luteolysis, unilateral effects on the functions of the ovary and tube. The transfer may be used as a therapeutic tool in order to obtain high local concentrations of drugs. It is postulated that a hormone releasing intra-uterine device (IUD) may have a local effect on the tubes and ovaries. It is also postulated that intrauterine instillation of cytotoxic drugs may be used before surgery in order to obtain a high concentration in local arterial blood when compared to the concentration in peripheral blood, thus obtaining a favourable therapeutic index between local beneficial and general toxic effects. The treatment may also create a high concentration of the drug in the local lymph glands and thus have a direct therapeutic effect on eventual metastasis.