The most cost effective way to eradicate illicit coca plants is to spray them with 2,4-D. Because natives who harvest coca leaves chew them and because the leaves are made into a paste that is widely abused, a study was undertaken to determine if the 2,4-D remained in the coca leaves treated with the herbicide and was found in coca paste made from the leaves. The coca plants used in the test were grown in a greenhouse and the testing was conducted in Beltsville, Maryland. Coca paste made from the leaves of plants that were basally treated with the herbicide did not contain 2,4-D. Trace amounts of 2,4-D were found in paste made from coca leaves that had been sprayed by a foliage application method. (Author abstract modified)