As people find relief from issues ranging from epilepsy to cancer, they might also be inadvertently creating other health problems for themselves thanks to the big problem of pesticide contamination in cannabis. Because the plant remains illegal at the federal level, some growers are not subject to federal regulation, which means they use whatever chemicals they please to grow commercial marijuana. Black market growers often go for the growing methods that offer the highest yield – and greatest profits – without worrying about how dangerous they are to people's health and that of the environment. As a result, many well-meaning cannabis users can't be certain what chemicals they are consuming.

Some people believe FDA regulation could help eliminate such dangers, but that seems unlikely and the problem looks like it is only going to get worse.