Dandelion tea is well known as an antibacterial and immune-boosting substance that has a potent list of organic compounds and natural acids to combat infections. If the duodenal ulcer is being caused by a bacterial infection, as many are, than the dandelion extract or dandelion tea can quickly neutralize it. Furthermore, dandelion tea is a diuretic, which helps to speed up urination and the expulsion of toxins from the body. Dandelion tea is quite potent, and should not be used for extended periods of time.