Guanidinium thiocyanate

Guanidinium thiocyanate is a chemical compound that can be used to deactivate a virus, such as the influenza virus that caused the 1918 "Spanish flu" so that it can be studied safely. Note: this compound may also be recognized as guanidine thiocyanate. This is because guanidinium is the conjugate acid of guanidine and is called the guanidinium cation, [CH6N3]+.

As a chaotropic agent, it is also used as a general protein denaturant, which is presumably the mechanism for its aforementioned application in humans.

Guanidinium thiocyanate is also used to lyse cells and virus particles in RNA and DNA extractions. A commonly used method is Guanidinium thiocyanate-phenol-chloroform extraction.