Researchers at Stanford University have made a sensational discovery: applying the common food dye tartrazine to the skin of mice allows you to temporarily see their internal organs and other structures. This dye is known as FD&C Yellow 5. It helps overcome the problem of light scattering caused by protein and fatty components of the skin that make it opaque. According to the study, tartrazine absorbs light in the near ultraviolet and blue part of the spectrum, which allows red and orange light to penetrate deeper into the tissues. The temporary transparency effect is easily reversible: just rinse off the dye. The scientists applied the technique to the abdomens of mice, observing neurons with fluorescent markers in real time. The dye was also applied to the skulls of the mice, allowing them to see the workings of brain blood vessels, and to the hind limbs, making the musculature visible. This discovery could greatly improve understanding of digestive problems. The researchers anticipate a significant increase in imaging depth, which could lead to new advances in biomedical research, including multiphoton imaging of the mouse brain and detection of tumors under centimeter-thick tissue without surgery.