Gammel Dansk is a Danish bitters, and the name literally means "Old Danish". It was first created in 1961 and it is flavoured with herbs and spices including star anise, nutmeg, ginger, laurel, gentian, Seville orange, cinnamon and others. The recipe remains a secret.

It is my favourite drink by quite some margin. It is an acquired taste, I sipped it first almost 30 years ago and only just managed not to spit it out. I was quite astonished to see that my Danish friends enjoyed it so I had another go. To cut the story short, it is a drink I am always bringing back from Scandinavian countries, and always run out of it shortly after. It is just brilliant, and highly immensely enjoyable.
Best cure for motion sickness ever, as long as it's taken early, before you feel unwell. Everything else I've tried is either unreliable or has side effects. I rode out a force 9 on a ferry in the North Sea able to walk about, eat and enjoy talking to the few people who were able to remain upright on the journey. It does taste medicinal, however, so don't expect to feel delighted until after you've downed it!
for a full stomach, gammel dansk is the best
too bad US stopped importing this a few years ago. it is by far the best
People either love Gammel Dansk or hate it, I have yet meet anyone without a strong opinion. I am among those that loves it, while my wife thinks it tastes like medicine. If you like exotic and complex flavors of the non-sweet variety you should at least try it. I have yet to taste anything truly similar. And thanks MoM, for making it available to the US.