We present the results of spectral studies of the interactions between butyrylcholinesterase and ethidium bromide fluorophore inhibitor. The ethidium bromide fluorescence selectively increased in the presence of butyrylcholinesterase. A rapid method for evaluation of serum butyrylcholinesterase activity is developed.

Spectral studies of the interaction between amanitine and ethidium bromide fluorophore showed the appearance of a new intensive fluorescence band after addition of amanitine to ethidium bromide solution, caused by the formation of a charge-transfer complex. The new fluorescence band is located in a shorter wave region of the spectrum compared to ethidium bromide fluorescence band. Based on the results, a rapid fluorescent method for detection of amanitines was developed.