The　antidiabetic　effects　of　Ge-Gen-Qin-Lian-Tang　decoction　(GQD)　have　been　proven　clinically.　In　a　pharmacological　study　conducted　on　STZ-induced　diabetic　rats,　the　constitutive　aggregates/sediments　of　Ge-Gen-Qin-Lian-Tang　decoction　exhibited　stronger　hypoglycemic　and　antioxidant　activities　compared　to　the　soluble　compositions.　This　study　aims　to　demonstrate　the　pharmacological　properties　of　aggregates　derived　from　GQD　by　measuring　permeability　of　the　active　monomer　phytochemicals　(e.g.,　baicalin)　in　a　Caco-2　cell　monolayer　and　determine　the　cellular　viability,　intracellular　redox　status　(MDA　and　SOD),　and　insulin　secretion　of　pancreatic　β-cell　line,　INS-1,　following　STZ-induced　oxidative　stress.　The　aggregates　were　separated　into　three　fractions,　namely,　＂MA　(microaggregates),＂　＂400　g　supernatant,＂　and　＂MNA　(micro-/nanoaggregates),＂　by　centrifugation　at　400　×g　and　15000　×g,　respectively.　Aggregates　in　the　sediment　increased　baicalin　absorption,　showed　little　toxicity　to　β-cells,　elevated　intracellular　SOD　levels,　and　significantly　suppressed　oxidative　damage　effects　on　cellular　viability　and　functions.　The　＂MA＂　fraction　had　a　larger　particle　size　and　provided　higher　antioxidant　cellular　protection　than　＂MNA＂　in　vitro,　implying　that　the　sediments　may　be　the　active　components　in　the　herbal　decoction.　The　actions　of　these　micro-/nanoaggregates　may　provide　a　new　perspective　for　understanding　the　antidiabetic　effects　of　herbal　decoctions　and　aid　in　interpretation　of　synergistic　actions　between　the　multiple　components.　©　2017　Dai　Lin　et　al.