Medicinal leeches are invertebrated parasites that have been used for medical purposes for centuries as one of the traditional treatment methods. Medicinal leeches are used for wound and flap healing in the plastic and reconstructive surgery, in the treatment of venous insufficiency, varicosities, hemorrhoids, and in many other diseases. However, due to medicinal leech therapy (hirudotherapy) complications such as anaphylaxis, local allergic reactions, anemia, and mucosal synechiae can occur. In this article, we report a case of an irritant contact dermatitis in a patient who experienced severe redness and itching after applying leeches for the relief of head and neck pain. Leeches are being used widely in some regions in the world and if people are informed about the leeches, it may be helpful in preventing complications that may occur.