Fluorouracil (5-FU) is one of the most essential drugs, and widely used to treat different types of cancers. However, direct injection of 5-FU causes many inevitable side effects, and therefore, the design of new and targeted drug delivery methods can reduce such undesirable effects. In the present work, density functional theory methods at B3LYP-D3(BJ)/6-31 g* level of theory were used to study the pristine and Al, Ga, P and As doped monolayer boron nitride (BN) nanosheets, as possible adsorption substrates for modern and targeted nanotechnology based drug delivery methods. Natural bond orbitals and quantum theory of atoms in molecules analyses were further used to reveal the physicochemical nature of the adsorption process. It was found that, adsorption process is endothermic in all studied cases, and the interactions energies are in the range of physisorption for pristine, P and As doped BN nanosheets, whereas, the chemical absorption of the 5-FU on Al and Ga doped nanosheets was obtained with adsorption energies of À 45.7 and À 46.3 kcal/mol, respectively. The calculated solvation energies also show that, the dissolution of the 5-FU/nanosheet complexes in water is more than the pristine nanosheets. The overall results confirm the great potential of the studied nanosheets and specially Al and Ga doped BNNSs as promising drug delivery substances in modern targeted drug delivery methods for 5-FU drug.