A new instrument has been designed to treat the primate uterine cornua and oviducts. 2 versions of the instrument are described. Both versions are 12 cm long. One is 3 mm in diameter, and the other is 3.5 mm. Tips may be manufactured to hold different volumes of fluid. The Teflon piston which is moved inside the tip, forces the fluid out through a small hole at the end. The piston is actuated from the proximal (operator's) end of the strument. Silicon rubber tubing may be filled with air or fluid from the stopcock at the operator's end through a fine tube which runs inside the instrument. In an attempt to determine if the instrument will locate fluids reliably and accurately, a vital stain, cresyl violet, has been used to inject normal sized uteruses in 6 patients prior to operation for various conditions. In 3 patients, both cornua were successfully stained with dye. In 2 patients, the cornu on only 1 side was seen to be stained, and in 1 patient, no stained areas were identified. Suggested applications of the instrument include: 1) investigation of oviduct physiology; 2) temporary sterilization; and 3) permanent sterilization.