Introduction: Plant derived mucilage has been explored as a drug, pharmaceutical excipient, and in cosmetics. Several mucilage and mucilage-containing drugs are being utilized in Unani medicine. These are to be standardized for authentications owing to immense utilization. A mucilage-containing drug obtained from root of Althaea officinalis L. (AO) – family Malvaceae, an important Unani drug, has been subjected to physicochemical studies for standardization. Materials and Methods: Mucilage of roots of the drug was isolated by classical and reference method. The physicochemical method included determination of ash values, moisture content, viscosity, swelling index (SI), and pH value. Powder characterization study included bulk density, tapped density, Hausner's ratio, and angle of repose. For preliminary phytochemical analysis, qualitative tests for organic constituents and test for mucilage were carried out. Analytical methods, namely Fourier transform infra-red (FTIR) and high-performance thin-layer chromatography (HPTLC) were also applied. Results: The yield percentage taken by acetone method was 36.80 ± 1.25 whereas that of classical method was 42.93 ± 1.35. Values of pH, loss on drying, viscosity, and SI were 4.08 ± 0.032, 14.46 ± 0.13, 34.40 ± 0.61, and 334.36 ± 23.77, respectively. Data for ash value and powder characterization (Micromeritic Properties) were set in. Preliminary confirmative test confirmed that the isolated polysaccharide is mucilage. HPTLC fingerprinting of aqueous extract gave 6 and 4 peak at 254 nm, 4 and 5 peak at 366 nm and 5 and 6 peaks at 550 nm in mobile phase chloroform (90): methanol (10): acetic acid (2). FTIR data for the mucilage were also set in. Conclusion: Physicochemical standardization data/monograph for AO root mucilage were developed.