N-Propylthiouracil Test Paper (PROP) is designed to determine the ability to taste this substance, determined by genetics. The taste can range from bland to bitter or even vile, depending on sensitivity to the chemical. The intensity of the bitter taste is determined by the homozygous dominant or heterozygous condition of the individual being tested. This paper is frequently utilized in taste studies that aim to identify Super Tasters. It has relevance in fields like food science, nutrition, and personalized medicine.