The use of Medicinal Opium was believed to be a "medical miracle"(Ward ) at first. People did not know about the highly addictive substance we know today. In Charles Dickens Bleakhouse, you notice a character who dies to overdosing on Opium. You also see characters struggling with the disease known as Gout. Opium would have been used to treat Gout, with people not knowing that it would most likely make the disease worse. In the Victorian Era in particular, Opium would be used to calm infants, not knowing that it would actually kill the babies. "Malnutrition rather than overdose killed teh children" since the opium reduced appetites(Ward). Eventually Great Britain would catch understanding of the addictive and dangerous tendencies of the drug. 

Fay, Peter Ward. The Opium War 1840-1842. Chapel Hill: University of North Carolina Press, 1975.

Wohl, Anthony S. Endangered Lives: Public Health in Victorian Britain. Cambridge: Harvard UP, 1983. pp. 34-35.