Okay. I know nothing about this stuff but it was listed a only still legal natural pain killer that you did not mention.
Wild Opium Lettuce (Lactuca serriola)
Opium lettuce grows throughout the world in various backyards and near roadsides. It loves to grow near asphalt. The plant is usually considered to be an invasive weed, and it certainly is the ugliest of the plants mentioned herein. When its leaves are scored, they release a milky sap. This sap mimics opium, hence its common name, "wild opium lettuce" or simply "opium lettuce". The plant's leaves are broken from the plant and scratched to release the sap. Then the sap is collected. It is a type of natural latex which is typically formed into pill-like balls. These can be directly consumed as pills, or smoked inside of a pipe. Opium lettuce is often reported to cause a numbing sensation that is felt spreading throughout the body. This feeling is particularly noticeable when the lettuce is smoked. It does not usually impart a euphoric or a "high" feeling.
There are few studies of opium lettuce in the Western world, but researchers in Iran have confirmed that opium lettuce was well known as a painkiller and sedative before the Victorian period. Thus, it is likely that it has been used for eons. In the paper,
Lettuce, lactuca sp. as a Medicinal Plant in Polish Publications of the 19th Century, the Institute for the History of Science affirmed,
"The action of the substance was weaker than that of opium, but free of the side-effects, and medical practice showed that in some cases lactucarium produced better curative effects than opium". Despite opium lettuce not containing opium, it has multiple characteristics that are similar to it. In addition to its pain-relieving properties, it is also known for assisting with coughs. It has even been used successfully in the mitigation of whooping cough (pertussis) symptoms.
The Servall Company published a catalog of medicinal plants in 1917, which was entitled
Health from Field and Forest. It stated that opium lettuce was
"highly esteemed to quiet coughing and allay nervous irritation, a good safe remedy to produce sleep, to be used when opium and other narcotics are objectionable". When it was written, codeine and opium were still widely available without a prescription. Both were considered to be safe and effective medicines, yet opium lettuce was known to be even safer.
Eating large doses of opium lettuce can cause nausea, vomiting, anxiety, and dizziness. So, it is probably best not to use it in a salad. The powdered leaves lack most of the effects of the sap, though the powder has a history of being used to remedy sunburns.