Collection of herbs at right maturity is one of such parameter which affect afficacy of medicinal plants. Standard reference markers used in quality control of herbal drugs mostly authenticate identity and not efficacy. In order to derive bioactive markers, knowledge regarding appropriate collection time for each herb is essential. Traditional medical knowledge is bioactivity-oriented and informs about best time of collection for certain medicinal species, as observed in case of Ipomoea mauritiana Jacq. (Vidari–Sanskrit). Only mature (bigger size) tubers of Ipomoea mauritiana are used by Traditional Medical Practitioners (TMP) for preparing galactagogues and immunomodulatory herbal medicines (Rasayan).Microscopy of transverse sections revealed structural variation between mature and immature tubers and girth of tubers determine the maturity of plant, the difference in phytochemical profiles of mature and immature tubers was observed.Variation in phytoconstituents of mature and immature tubers was confirmed through proximate analysis, phytochemical screening, qualitative HPLC and HPTLC analysis revealed the variation in phytoconstituents in mature and immature tubers. Keywords: Microscopy, HPLC, HPTLC, proximate analysis, phytochemical screening.