ABSTRACT
We experienced a case of erythema nodosum of unknown etiology successfully treated with therapy based on Kampo diagnosis. The case was 44 year-old woman who had erythema nodosum over her bilateral leg extensors several times a month, became cold easily and had stomatitis. At first, we administered seinetsuhokito, which resulted in the disappearance of her stomatitis. However, she still had a recurrence of her erythema nodosum. Because of a condition of interior heat and qi counterflow, we considered her situation heibyo. We administered seinetsuhokito and byakkokakeishito every other day, which resulted in the disappearance of both her stomatitis and erythema nodosum. Therefore, we suggest that it is worthy to think about heibyo situations, when treating patients with complications.