Phyto-natural products are deeply associated with ethno-medicinal practices with less or more scientific validation for curing many vital diseases. Thus, the present study was carried out to asses chemical constituents and bioactivities of Grantia aucheri Boiss at different growth stages (vegetative, flowering, and seeding). For this aim, the chemical composition of G. aucheri ethanolic extracts was analyzed by gas chromatography with mass spectrometry detection (GC–MS), their total phenolics, total flavonoids, total tannins, and total anthocyanins concentrations were also spectrophotometrically determined. Antifungal and antibacterial activities were determined against three pathogenic fungi and six human pathogenic bacteria. Furthermore, antioxidant activity (DPPH and ABTS scavenging) and anti-inflammatory activity (Human Red Blood Cell Stabilization Method) were evaluated. The highest content of total phenolics, total flavonoids, total tannins, and total anthocyanins were established in the extract of G. aucheri at its flowering stage. Such phyto-compounds as boranyl acetate, β-himachalene and himachalol were major compounds found among 34 chemical constituents identified. The best antioxidant, anti-inflammatory, antifungal, and antibacterial activities were also found for this extract. Its phytochemicals presented bactericidal activities, mainly against Staphylococcus aureus, Bacillus subtilis, and Streptococcus pyogenes along with moderate fungicidal activity, however, it was less effective than the first one. Apart from antioxidant, antimicrobial, and anti-inflammatory activities, chemical constituents of G. aucheri may be potential alternative biomedical applications to reduce synthetic chemicals drugs.