During the manufacture of the munition nitroguanidine (NQ), wastewater is contaminated by NQ and related by-products. Land application of the NQ-contaminated wastewater was initiated after discussions with the Kansas Department of Health and the Environment and the US Environmental Protection Agency. This treatment method has been a cost-effective and convenient means of disposal. The environmental fate of NQ is related to plant uptake and metabolism as well as metabolism by plant consumers and decomposers. Toxicity of NQ in vertebrates has been found to be very low. Land application of NQ-contaminated wastewater will result in NQ penetration into the root zone where the potential for absorption exists. However, virtually nothing is known of the uptake and metabolism of NQ in plants. The objective of this study was to test the toxicity of and to characterize the uptake of NQ in plants.