Cannabis may improve the effectiveness of drug therapy for the hepatitis C virus (HCV), a potentially deadly viral infection that affects more than three million Americans91. Treatment for HCV involves months of therapy with two powerful drugs, interferon and ribavirin, both of which have severe side effects, including extreme fatigue, nausea, muscle aches, loss of appetite and depression.

Due to these side effects, people often do not finish treatment, which worsens their symptoms and can promote harm to the liver. Researchers from the University of California, San Francisco medical school and the Organization to Achieve Solutions in Substance-Abuse (OASIS) found that “modest cannabis use may offer symptomatic and virological benefit to some patients undergoing HCV treatment by helping them maintain adherence to the challenging medication regimen.” Other research found that people combating HCV who used cannabis while undergoing combination ribavirin and interferon treatment were about three times more likely to complete their conventional medical treatment than those participants who did not use cannabis. These studies indicate that for patients fighting HCV, cannabis-based medicine improves appetite and offers psychological benefits such as reduced depression that help them tolerate the treatment's unpleasant side effects.


Sylvestre, D. L., Clements, B. J. & Malibu, Y. Cannabis use improves retention and virological outcomes in patients treated for hepatitis C. Eur J Gastroenterol Hepatol 18, 1057–1063 (2006).