10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 2 2013 (April - June) The present study is designed to investigate the serum immunoglobulins viz. IgA, IgG and IgM after sub-acute (80ppm, 1h/d for 30 days) and sub-chronic (80ppm, 1h/d for 60 days) exposure to SO lessThan sub greaterThan 2 lessThan /sub greaterThan gas in albino rat. The rats six sets- control set (I) and (IV) exposed to ambient air for 30 and 60 days, experimental set (II) and (V) exposed to SO lessThan sub greaterThan 2 lessThan /sub greaterThan  gas for 30 and 60 days and experimental set (III) and (VI)exposed to SO lessThan sub greaterThan 2 lessThan /sub greaterThan gas with pre-exposure supplementation of aqueous extract of ashwagandha root (5mg/rat/day) for 30 and 60 days. The result of the present study shows a significant decrease in IgA, IgG and IgM after 30 days exposure to SO lessThan sub greaterThan 2 lessThan /sub greaterThan gas, while a very highly significant decrease after 60 days exposure to SO lessThan sub greaterThan 2 lessThan /sub greaterThan gas. However, an increase in values of serum immunoglobulins were observed after supplementation of aqueous extract of Ashwagandha. Modulation in serum immunoglobulins after supplementation of Ashwagandha extract is due to antioxidant defense mechanism against SO lessThan sub greaterThan 2 lessThan /sub greaterThan toxicity. PREETI KUMARI, ASHA AGARWAL AND RAJNI SINGH Ashwagandha, immunoglobulins, SO2, albino rat. 790-794