Laudanum is an alcoholic tincture of opium, sometimes sweetened with sugar and also called wine of opium. The 19th century was marked by the widespread use of laudanum as it was cheaper than a bottle of wine as it was not taxed as an alcoholic beverage. The addictive properties were not known and in some cases Laudanum was consumed with Absinthe, like Johnny Depp does in the movie "From Hell".
This small bottle is empty, but still has its original cork (don´t try to consume any of the substances that are still in the bottle, this is highly poisonous!). On the side of the bottle you can read "Cuillerées a Cafe" and a measuring scale.