As Wikipedia points out, Rhus toxicodendron is an older name for poison ivy, which causes an itching, painful rash when touched. Under the names Rhus toxicodendron or Rhus tox, it is a homeopathic remedy for arthritis and other conditions, but its effectiveness is questionable, according to Healthline.
The British Homeopathic Association suggests the use of Rhus toxicodendron for those with stiff or inflexible joints due to arthritis, fevers caused by infections, such as influenza, and blistering skin diseases, such as eczema. According to Healthline, Rhus toxicodendron is typically administered as a pill, ointment or gel. Preliminary studies do not show that it is effective on humans. Side effects include rash and swelling in the lower extremities.