Fever bark. The name leaves us almost no mystery. Just as it is aptly titled, fever bark was originally taken to treat fevers, specifically malaria. However, there is no evidence or support that shows fever bark is an effective supplement to treat malaria. Nevertheless, fever bark has other uses as well! The bark of the stem and root is antispasmodic and hypotensive, good for treating involuntary muscle spasms and high blood pressure respectively. Fever bark has also been used to treat diarrhea.