Standardization is an important measurement for ensuring the quality control of herbal drugs. It has become essential to develop reliable, specific and sensitive quality control methods. One of the prime ingredients of Ashwagandhadi lehyam is Withania somnifera L. Dunal (Solanaceae) (ashwagandha). In the present study, Ashwagandhadi lehyam was formulated and the quality assessment of the formulation was based on phytochemical screening and physico-chemical evaluation. Ashwagandhadi lehyam was formulated according to a working formula and subjected to phytochemical screening by FTIR analysis and HPTLC fingerprinting, heavy metal determination by AAS, determination of alcohol content, tested for Escherichia coli, Staphylococcus aureus, aerobic bacteria, yeasts and mould, oral toxicity studies and anti-epileptic activity by MES method. The physico-chemical studies showed total ash content as 6.45%, extractive values and some trace elements such as lead, mercury, cadmium and arsenic with 3.2, 0.05, 0.18 and 0.48 ppm, respectively. FTIR and HPTLC studies revealed the presence of functional groups of withanolides in Ashwagandhadi lehyam, resulting in its chemical standardization. The formulation exhibited less epileptic seizures in various phases when compared with that of standard phenytoin and found to possess better anti-inflammatory activity, thus making it biologically standardized. The physico-chemical and pharmacological analysis to standardize Ashwagandhadi lehyam confirmed its use as a safe anti-inflammatory agent and for various seizure disorders.