7. Interferons

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This class of drugs is often used to treat serious diseases such as leukemia, multiple sclerosis and hepatitis. While we can imagine some instances where it would be a benefit to lose the ability to smell, like if someone had to live next to a paper mill or a sewage treatment plant, most of us value our sense of smell and would not want to lose it. In some cases, people who are on interferon drugs do lose their sense of smell, and although much of the time it is a temporary condition, there are some patients who are still experiencing the problem even a year after they have stopped taking the drug.