In　this　study,　gold　nanoparticles　are　synthesized　through　a　conventional　redox　reaction　in　water　and　characterized　by　means　of　TEM,　DLS,　XRD　and　UV–visible.　The　average　diameter　of　gold　nanoparticles　is　attained　as　18　nm.　Then,　cetirizine　drug　is　loaded　on　the　as-prepared　gold　nanoparticles　in　an　aqueous　colloidal　solution.　This　investigation　shows　that　the　peak　of　plasmon　resonance　is　sensitive　to　the　concentration　of　drug,　therefore　a　tentative　description　is　disclosed　for　this　purpose.　In　addition,　a　green　light　source　is　adopted　with　the　wavelength　of　plasmon　peak　of　gold　nanoparticles　to　excite　the　surface　plasmons　and　induce　release　of　the　drug　molecules.　Then,　the　release　profile　is　studied　by　UV–visible　spectroscopy.　It　is　found　that　the　peak　of　surface　plasmons　shows　a　distinct　blue　shift,　dependent　upon　the　time　of　light　irradiation.　Plotting　numerical　data　to　the　experimental　curves　for　the　absorption　peaks　gives　interesting　information　on　the　loading/release　behavior　of　cetirizine　on　the　gold　nanoparticles.　The　experimental　data　were　fitted　well　with　an　exponential　fucnction　and　we　found　that　~63%　of　the　drug　was　released　into　the　solution　after　about　7　min　radiation.　These　results　clearly　show　that　the　emitting　green　light　can　release　the　drug　molecules,　as　can　be　detected　by　UV–visible　absorption　experiment.　Outputs　of　this　study　offer　a　new　insight　on　the　investigation　of　drug　delivery　by　using　excitation　of　surface　plasmon　resonance　from　gold　nanoparticles.　Finally,　the　performed　cellular　cytoxicity　and　inhibitory　dose　IC50　of　Au@cetirizine　nanoparticles　on　nasopharyngeal　carcinoms　cell　line　(C666–1)　showed　that　this　nanoparticle　has　an　acceptable　cytotoxicity　toward　the　examined　cell　line　and　a　decrease　in　the　MTT　signal　was　attained　compared　to　the　untreated　cells.　©　2021　Elsevier　B.V.