The prickly ash, native to North America, has a long tradition of use for alleviating toothaches. In fact, it's often called the "toothache tree." It also is traditionally used to treat rheumatism as well as fungal infections. The active ingredient in prickly ash bark is called xanthoxylin. Laboratory and animal studies do confirm that it has anti-fungal and painkilling properties. However, clinical studies don't support its use. Ingesting prickly ash bark can cause side effects.
Common side effects for prickly ash bark include nausea or vomiting, according to "The Essential Herb-Drug-Vitamin Interaction Guide," by George T. Grossberg and Barry Fox. Prickly ash also may irritate the gastrointestinal tract, which can worsen infectious or inflammatory gastrointestinal ailments.
Using prickly ash can cause photosensitivity, meaning that it makes your skin sensitive to sunlight, according to Grossberg and Fox.
It's possible to have an allergic reaction to prickly ash, advises the "Handbook of Medicinal Herbs," by James A. Duke. If you experience one, you should quit using the supplement immediately and seek medical attention. Other names for this tree include angelica tree, suterberry, pepperwood, wild orange and Hercules' club. Northern and southern prickly ash plants are similar, with the southern variety growing taller than the northern, according to Purdue University in Indiana. Prickly ash is part of the Rutaceae, or rue family, which also includes the kumquat, according to the U.S. Department of Agriculture.
Low Blood Pressure
Prickly ash can cause low blood pressure, technically called hypotension. You also increase risk of bleeding when you use prickly ash along with herbs that affect platelet aggregation, or the ability of blood to clot, according to Grossberg and Fox. Bleeding and bruising risk is raised when you take prickly ash with certain drugs as well, such as warfarin, heparin, tinzaparin and aspirin.
Prickly ash may interfere with your ability to absorb drugs meant to replenish your iron stores or hemoglobin, according to Grossberg and Fox. Examples include iron-dextran complex, polysaccharide-iron complex, ferric gluconate and ferrous sulfate.