In this work, I present the first extended application of the QFD approach, which combines quantum mechanical (QM) and ab initio DFT calculations with traditional docking procedures. Specifically, this new method is employed to identify nontoxic natural products as potential inhibitors of Indoleamine 2,3-dioxygenase 1 (IDO1)-a protein that plays a crucial role in combating Alzheimer's disease, Parkinson's disease, and cancer.