In 1830, Dr. Siegert exported his unique aromatic bitters to England and Trinidad. By 1850, he had resigned his commission in the Venezuelan army, to concentrate on the manufacture of his bitters, since by then demand had leapt ahead of supply. By the time Dr. Siegert died in 1870, his reputation and that of his Angostura aromatic bitters were internationally established. Dr. J.G.B. Siegert& Hijo, a partnership with his son, Carlos, was established in 1867 by Dr. Siegert. Two years after the death of Dr. Siegert, the name was changed to Dr. J.G.B. Siegert& Hijos, to include younger brother, Alfredo Siegert.Don Carlos, as Carlos became known, recognised that he was in possession of the secret to a unique product. Bon vivant, impeccable in his dress and manners, he was among the first advertisers. He exhibited in London in 1862 and sampled his product. It was applauded with gin, the monotony of which was forever altered. It became the magic ingredient, to be used in exotic concoctions.

Underberg is an aid to wellbeing. The careful balance between the valuable herbal ingredients and premium-quality alcohol gives Underberg its soothing, digestive properties. Underberg results from the power of choice, aromatic herbs from 43 countries. There is scientific proof that it stimulates the digestive system. The natural Rheinberg Herbal Digestive contains no added sugar.