Senna is an herb, and senna tea is made from the leaves of the Cassia senna plant. These plants thrive in tropical areas, though some can grow in more temperate climates. Thanks to its ability to treat constipation, it’s sometimes used short-term to treat hemorrhoids. However, there is insufficient evidence to support the use of senna for hemorrhoids or weight loss. Caffeine free tea that can be enjoyed hot or chilled.