Swedish bitters is a traditional herbal tonic, said to have been formulated originally by Paracelsus and rediscovered by 18th Century Swedish medics Dr. Claus Samst and Dr. Urban Hjärne. In modern times it has been popularised by Maria Treben, an Austrian herbalist. It is claimed to cure a large number of ailments and help digestion. However these claims are presented with little in the way of scientific evidence to back them up.
There are variations on this recipe and herbal shops supply alcoholic and non-alcoholic versions of the drink. The alcoholic Swedish bitters is reported as having a similar flavour to Angostura bitters, though perhaps a little drier.
The following herbs are added to alcohol to make Swedish Bitters 
- aloe (active ingredient)
- water extract of the following herbs:
- www.MotherNature.com - Swedish Bitters