Interesting fact, the Pils beer is, assumingly, named after the Bilsenkraut which was used instead of hop long before the german purity law was enforced by the church. But, the Bilsenkraut is a drug which also affected the sexdrive of people drinking beer (and hitting the lethal dose is very easy too), so they (by which I mean, 'The Church') started experimenting with different ingredients and ended up with Hop which results in beer that stops the sexdrive almost completely and also darkens the mood of the user.
Source: http://de.wikipedia.org/wiki/Schwarzes_Bilsenkraut