Wikipedia
Centerbe or Centerba, translated as "one hundred herbs", is a traditional Italian liqueur of light green colour made of digestive and aromatic herbs found in the Majella, an appendix of the Apennine Mountains. It is made in Abruzzo, Italy and it contains 70% alcohol. The liqueur comes in two strengths: strong and mild. The strong centerba is considered to be beneficial for the digestion but it can also be applied externally as an antiseptic. It was originally manufactured by Beniamino Toro in Tocco da Casauria in 1817.
It has a very high alcoholic content, usually 60 to 150 proof (30 - 75%). Homemade Centerbe can be made by placing orange leaves, basil, chamomile, rosemary, sage, juniper, cloves, cinnamon, toasted coffee beans, saffron, mint, lemon leaves, mandarin leaves, thyme blossoms, and marjoram in a bottle, pouring alcohol over the whole thing, and letting the mixture macerate, covered, for at least 30 days, then straining it through a cloth napkin and adding a sugar syrup. Aged at least one month, Centerbe is an excellent digestive drink.
'White Unsweetened Centerbe' is an ingredient in the forgotten, presumably French, Coup de Foudre ['Love Struck'] cocktail, included in the United Kingdom Bartenders Guild's '1700 Cocktails' (1934). Verbatim, the recipe is: 1/3 White Unsweetened Centerbe', 1/3 Red Curaçao, 1/3 Coates Plymouth Gin. Serve with a small piece of candied orange peel.
'Unsweetened' suggests that, at that time, a strictly medicinal version of Centerbe was available, perhaps similar to the homemade recipe above without the sugar syrup. Alternatively, many of the 18th century sweet recipes are, to modern tastes, exceptionally sweet. So perhaps standard Centerbe was routinely sweetened to make it palatable. Bols and Grand Marnier both formerly made red curacaos. Coates, then owners of Plymouth Gin, subsidised the publication of 1700, and in return became the 'named' gin brand in almost all the recipes.