Coca, though it is a forbidden to even bring a tea bag’s worth to the United States*, is actually a folk cure-all that has no narcotic effects without extensive processing. In rural communities, coca is one of the elements that sponsor social cohesion as well as spirituality. An ethnography, The Hold Life Has by Catherine Allen, pursues these links in detail. Before the Spanish arrived, coca was an important part of the economy of the state-level societies such as the Inca. None of this matters to Batman though, as you can see in this comic from 1988:
*Though you can buy it from Amazon.com (?)