View photos of the medicinal plant Ericameria laricifolia (Turpentine bush), profiled in Medicinal Plants of the American Southwest.

A passage from Medicinal Plants of the American Southwest:

Turpentine bush has a sedating effect on smooth musculature and to some degree on the central nervous system. Traditionally, the plant has been used in treating convulsions and spasms, particularly if initiated from moving from a hot environment to a cooler one in a short time period. A warm poultice can be applied to local pain and spasm, such as over the abdomen for menstrual, intestinal, or stomach cramps. Internally the plant is decidedly stimulating to menses.