A new steroidal sapogenin molecule 1 having unique characteristics, 21-nor and unusual C19 carboxylic acid has been isolated from the roots of Asparagus racemosus. On the basis of chemical evidence, extensive spectroscopic analysis including two dimensional (2D) NMR and X-ray studies of single crystal, the structure of 1 was determined as (1 S,2 R,3 S,8 S,9 S,10 S,13 S,14 S,16 S,17 R,22 R,25 R)-21-nor-18β,27α-dimethyl-1β,2β,3β-trihydroxy-25-spirost-4-en-19β-oic acid. 1 crystallizes in monoclinic space group P2 1 with a = 9.295(2), b = 11.238(2), c = 11.376(2) Å; β = 91.993(4)°, Z = 2, D cal = 1.344 Mg/m 3. The structure was solved by direct methods and refined by full-matrix least-squares procedure to a final R-value of 0.0561 for 4064 observed reflections. 1 was tested against the type of immune responses generated during treatment in normal and immune-suppressed animals and detailed biological activity evaluation suggests it to be a potent immunostimulator.