Roundup weed killer does not contain paraquat (and paraquat does not contain Roundup), but both herbicides are similar in their popularity among agricultural operations and their potential health risks. While glyphosate, the active ingredient in Roundup, is alleged to cause cancer, including non-Hodgkins lymphoma and chronic lymphocytic leukemia (CLL), paraquat is alleged to cause Parkinson’s disease. To be clear, both Roundup and Paraquat are potentially dangerous herbicides that may pose serious health risks to those exposed.