Systemic contact dermatitis (SCD) develops when a person who was previously sensitized to an allergen is exposed to the same allergen via the systemic route. In East Asia, the use of lacquer for polishing furniture is common and a part of the traditional culture. Contact exposure to tableware polished with Rhus lacquer may lead to sensitization. In Korea, SCD is commonly observed after systemic exposure to Rhus, a nutritious food item consumed because of the common belief of it improving the immune system. In this study, we reviewed the medical records of 21 Korean patients with SCD caused by Rhus ingestion. We found that the most significant epidemiological factor for SCD was the season of the year. Furthermore, 66.67% of the patients presented with leukocytosis and 23.81% showed increased liver enzyme levels. Therefore, it is important to educate people on the risks associated with the systemic ingestion of Rhus.