According to the Reinheitsgebot of 1516, only four natural ingredients can be used for the production of beer: water, malt, hops and yeast.
This is stipulated in the Reinheitsgebot, which is valid still today, and is thus the oldest regulation relating to foodstuff worldwide.
This regulation was meant to ensure sterility and exclude harmful chemicals or other additives. This was because before hops was used to preserve fragrance in beer, all types of other herbs were used for seasoning. Some of them were toxic and caused the drinkers to hallucinate.
What did they use?
Ox gall, juniper, sweet gale, blackthorn, oak bark, wormwood, caraway, anise, bay laurel, yarrow, datura, gentian, rosemary, common tansy, amber, spruce buds, pine roots, and especially henbane.
The Reinheitsgebot of 1516 is still in use today. It grants an effective consumer protection: German beer does not contain any artificial flavours or additives – just water, malt, hops & yeast.