View photos of the medicinal plant Datura wrightii (Sacred datura), profiled in Medicinal Plants of the American Southwest.

A passage from  Medicinal Plants of the American Southwest:

Datura is one of the strongest analgesic herbs we employ. Its influences are strong, drug–like, and potentially toxic. The leaf poultice, oil, or liniment will give symptomatic relief to swollen and painful sports injuries, contusions, sprains, and the like. The freshly pureed leaf, alone or mixed with Prickly pear or Aloe leaf pulp, is soothing and will relieve pain from burns.