Modern authors usually suggest that widespread opium use was a major health problem during the 19th century. However, the use of opiates must be kept in proper perspective with other contemporary health problems. Mortality from cholera, malaria, and dysentery was very high, and opiates provided some relief from these illnesses (Opiates remain the most effective treatment for dysentery.). Some authors have suggested that the easy availability of opiate-based medicines saved more lives than it took. As the deleterious effects of chronic opiate use became increasingly recognized during the late 19th century, several factors helped ease the need for opiates: the improvements in sanitation diminished cholera and dysentery, the drainage of swamp lands decreased malaria, and the introduction of acetylsalicylic acid (aspirin; 1899) provided an alternative medicine for moderate pain relief.
http://wings.buffalo.edu/aru/preprohibition.htm
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