Prickly Ash Bark (Zanthoxylum americanum or Zanthoxylum clava-herculis) has a longstanding history of use in North American herbal medicine, particularly within Native American and eclectic medicine traditions. Historically, it has been used as a general circulatory stimulant and as a remedy for various conditions, including digestive complaints, toothache, and rheumatic pain. Some traditional sources also mention its use in supporting female reproductive health, including menstrual irregularities such as delayed or absent menstruation (amenorrhea). The rationale in traditional systems is typically based on its reputed ability to stimulate blood flow and "move the blood," which was interpreted as potentially beneficial for irregular menstruation.

However, there is a lack of high-quality scientific evidence to support these uses. Modern clinical studies specifically evaluating Prickly Ash Bark for the treatment or support of menstrual irregularities are lacking. Most references to its use for menstrual issues are anecdotal or found in historical herbal texts rather than contemporary research. Therefore, the justification for its use in this context is primarily traditional and should not be interpreted as scientifically validated or evidence-based. Those considering its use should consult qualified healthcare practitioners, especially since safety data for this indication is also limited.