A mouse tail vein catheter is used in research labs to facilitate the administration of substances, such as drugs or experimental compounds, into the bloodstream of mice. This technique is commonly employed in pharmacology, toxicology, physiology, and similar areas of research. The catheter is typically inserted into the tail vein of a mouse, providing a reliable and relatively non-invasive route for delivering substances directly into the circulatory system. This method allows for precise control over the dosage and timing of the substance administered. It is useful when repeated or continuous administration is necessary, such as in long-term studies.