The increasing use of pesticides in agriculture and gardening has caused severe deterioration to both theecosystem and the health of users (human beings), so there is an urgent need for eco- and user-friendly pesticides. Among avariety of herbicides, paraquat (PQ), frequently used as an effective herbicidal agent worldwide, is well-known for its serioustoxicity that has killed, and harmed, thousands of people and countless wildlife such asfish. Herein, we present a facilesupramolecular formulation of PQ@cucurbit[7]uril (PQ@CB[7]), prepared by simply mixing PQ with equivalent (molar)CB[7] in water. With addition of CB[7], PQ’s cellular uptake was dramatically inhibited. The reactive oxygen species (ROS)generation and the associated apoptosis otherwise induced by PQ in cellular models were both reduced, resulting in increasedcellular viability. In a wildtype zebrafish model that is a typical fragile wildlife species in the ecosystem, the supramolecularformulation exhibited significantly reduced hepatotoxicity and increased survival rate, in comparison with those of thefishexposed to free PQ. In a mouse model that is clinically relevant to human being, the administration of PQ@CB[7] significantlyalleviated major organ injuries and unusual hematological parameters that were otherwise induced by free PQ, resulting in asignificantly increased survival rate. Meanwhile, this formulation maintained effective herbicidal activity that was equivalent tothat of free PQ. Taken together, this facile supramolecular PQ formulation is providing not only an extremely rare example of aneco- and user-friendly herbicide that has been desired for decades but also a practical solution for green agriculture.