In this case, we report a case of Soeumin rectal cancer patient who was mistreated with herb medication. This patient was 72 years old female diagnosed rectal cancer stage IV with multiple liver, lung, and LN metastases. She administered our cancer center in Sep. 2011 for cancer treatment, we diagnosed this patient as Taeyangin at first, and treated with Mihuedungsikjang-tang. After 1 week, she complained upper abdominal discomfort, severe abdominal pain, nausea and sweating. Considering several symptoms and conditions, the change of symptoms seemed to a adverse events caused by mistreatment. We re-diagnosed this patient as Soeumin, and treated with Soeumin herbal medication, Baekhaoleejung-tang(白何烏理中湯) and Hyangsayangyi-tang(香砂養胃湯). Several symptoms including abdominal pain were improved 2 weeks later. Therefore, we report this case as a reference that Soeumin misdiagnosed as Taeyangin and the improvement of adverse symptoms.