The most bitter compound known is denatonium-- it was discovered in 1958 by Macfarlan Smith of Edinburgh, Scotland during a research study on local anesthetics. The salts of denatonium are almost always colorless and odorless solids.
The bitterness of the compound has guided many of its applications in denatured alcohol, antifreeze, nail biting preventions, animal repellents, liquid soaps, and shampoos. Interestingly, despite its bitterness even in astoundingly small concentrations—denatonium is not known to be harmful or pose any long-term health risks. However, exposure is obviously unpleasant and can be irritating.
Watch the video above to learn more!