Bulnesia sarmientoi is a tree that inhabits a part of the Gran Chaco area in South America, around the Argentina-Bolivia-Paraguay border. Its wood is often traded as "Paraguay lignum vitae", since it has properties and uses similar to the "true" lignum vitae trees of genus Guaiacum, which are close relatives. Another trade name is "vera" or "verawood", which may also refer to the even more closely related B. arborea. Another common but rather ambiguous name is palo santo, which it shares with the species Bursera graveolens.

The Gran Chaco or Dry Chaco is a sparsely populated, hot and semiarid lowland tropical dry broadleaf forest natural region of the Río de la Plata basin, divided among eastern Bolivia, western Paraguay, northern Argentina, and a portion of the Brazilian states of Mato Grosso and Mato Grosso do Sul, where it is connected with the Pantanal region. This land is sometimes called the Chaco Plain.