Polycyclic aromatic hydrocarbons (PAHs) are combustion-related pollutants and are ubiquitous in the environment, including in sources of drinking water. Upon contact with DNA, stable PAH-DNA adducts form rapidly as the first step towards their toxic effects. In this work, we prepared hydrophilic DNA nanogels to exploit this generic complexation process as a biomimetic scavenging method. This approach relies on interaction between PAHs and the complete network that constitutes the water-swollen nanogels, and is not restricted to interfacial adsorption. Up to 720 mu g of PAH per gram of DNA nanogel are taken up, meaning that 1 mg of DNA nanogel is sufficient to purify a liter of water containing the critical PAH concentration for cancer risk (600 ng L-1). As a result of short diffusion pathways, PAH uptake is rapid, reaching 50% loading after 15 minutes. Beyond PAHs, DNA nanogels may be useful for the generic detoxification of water containing genotoxins, since most known molecules that strongly associate with DNA are mutagenic.