A toxic organic substance with the chemical formula C20H19NO5 which is found in the roots of certain plants such as barberry and golden seal. It kills amoebas (is an amebicide) and is used to treat cholera. It cannot be dissolved in water, but is soluble in alcohol and ether. It has a melting point of 145 degrees Celsius when dry. As a solid, it is a white to yellow crystalline alkaloid.