The heroin kits in WW1 is perfectly true. This was the age where laudanum (tincture of opium) was sold over the counter. It was very popular with women for ‘headaches’ which I suspect included period pain.
The medical fraternity had a high regard for heroin, considering it a ‘sovereign remedy’ for a whole bunch of things. Found this article about the history of heroin .
"At the end of the 19th century in both America and Britain, opium and morphine were popular for medical and recreational purposes. While heroin was first derived at about this time by boiling morphine, it would be a while before it too would become a popular drug.
Working-class families in England used opium for all types of illnesses and injuries. Coughs (common for those with tuberculosis or pneumonia), sleeplessness or injuries would be soothed by these drugs. Many of those who supplied the drug were not doctors, and overdoses were not unusual. Some mothers who gave the drug to calm fussy babies inadvertently killed them by giving too much."
-------------------------In 1898, the Bayer pharmaceutical company began an aggressive marketing campaign to sell its commercial preparation of Heroin. That was the name they gave to their formulation of diacetylmorphine, or the product of boiling morphine for several hours. Heroin was heavily promoted as being non-addicting, and therefore an excellent treatment for morphine addiction. Bronchitis, tuberculosis and other cough-inducing illnesses were also treated with Heroin. In 1906, the American Medical Association approved Heroin for general use and recommended that it be used in place of morphine."
I guess the story about hemp is anecdotal, but it has the ring of truth.