phenylthiocarbamide

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A crystalline compound, C₆H₅NHCSNH₂, that tastes intensely bitter to people with a specific dominant gene and is used to test for the presence of the gene. Also called phenylthiourea.

Wiktionary

1. n. organic chemistry The N-phenyl derivative of carbamide; it is either tasteless or has a bitter taste, depending on the genetic makeup of the person tasting it