The crystal and molecular structure of (1-n-butyl-2,6,6'-trimethyl-4-oxo-4,5,6,7 - tetrahydro - 3 indole acetic acid) with desirable anti hyperglycemic properties is reported. The title compound crystallises in orthorhombic space group Pbca with z = 8. The unit cell dimensions are a=15.698(13)Angstrom, b=11.639(2)Angstrom. c = 18.506(3)Angstrom. V = 3381.2(29)Angstrom (3), Deal = 1.145Mg/m(3). The cyclohexane ring adopts a sofa conformation. The structure is stabilized by C-H---O and O-H---O hydrogen bonds. Molecular modeling studies on this class of compounds and the classical antidiabetic agent tolbutamide reveal a structural basis for the similar biological activity exhibited by two totally structurally unrelated compounds.