Asarum is a little poisonous, but external use won't have any effect.

This prescription is mainly used for warming kidney and dispelling cold. If you are afraid of cold, pale face, mental fatigue, weak waist and knees, loose stool, excessive urination, and fat tongue, you can use this recipe.

But if your dysmenorrhea belongs to qi stagnation and blood stasis, damp-heat betting, qi and blood weakness, liver and kidney deficiency and so on. This prescription is not suitable.