Laudanum is the name of a tincture containing opium. Paracelsus thought that it was good for treating almost anything. According to Paracelus, laudanum consists of about 9 parts wine, and one part opium. Other ingredients, such as henbane, mandrake and deadly nightshade were commonly added. Since its discovery in the 16th century, laudanum was often used to treat different diseases. Its popularity and use is comparable to the modern drug aspirin. Its main effect was that of the opium: it was a painkiller, and a sedative.
The main problem is that opium causes addiction. This was only seen starting with the 19th century. Towards the end of the 19th century, there were good alternative drugs. England banished opiates in the 1920s, Germany regulated their use in 1929.
Laudanum, like other opiates was used as a painkiller, and a sedative. Until the 1970s it was used to treat clinical depression. Laudanum is dangerous to children, it is easy to get an overdose. Today, laudanum is still used to treat severe cases of diarrhea which sometimes occur with chemotherapy.