Whatever chelator is in cilantro apparently is rather rare in that it can move inorganic mercury across the blood brain barrier. However for most people just starting to chelate, this will most likely mean it will move mercury *into* the brain and cause an increase in brain-related symptoms.
Lipoic acid also moves Hg across the bbb. Inappropriate use of it caused the mice in this study to have more Hg in the brain. http://onibasu.com/archives/am/74605.html