In the beginning of the 20th century two devastating pandemics swept Europe and North America at approximately the same time, the Spanish Flu and the Encephalitis lethargica (“sleeping sickness”). The Spanish flu was known to be caused by Influenza A virus, whereas the Encephalitis lethargica’s etiology remains a mystery. One of the most successful treatment of this encephalitic parkinsonian syndrome was the Bulgarian treatment, major component of which is Atropa Belladonna.

In this overview of the pandemics and science we will explore one of the mechanisms that could have led to the explosion of Encephalitis lethargica, as possible complication of the Influenza A virus infection, connecting the two pandemics.

We will also review the herbal action of Belladonna alkaloids on different body systems that could explain the success of the Bulgarian treatment. Description of the Bulgarian treatment will also be discussed, along with the rational use of its herbals and dietary components.