BACKGROUND:Adathodai Chooranam is a Siddha Poly herbal formulation which is specially indicated for Bronchial Asthma in Siddha Sastric text. The toxicological profile of the drug was not reported. OBJECTIVE: The present study was undertaken as per WHO Guidelines to establish the toxicity profile of Adathodai Chooranam in an experimental animals which will render strong evidence for its safety in clinical use of Bronchial Asthma. METHOD:In acute toxicity study a single oral dose (10× Therapeutic dose) of Adathodai chooranam 2.6 gm/kg body weight was administered in Swiss albino mice and the animals were observed for 14 days. Gross pathology was performed at the end of the study. In long term toxicity study Adathodai Chooranam was administered in wistar albino rats at 270 mg/Kg body weight, 1, 350 mg/kg body weight, 2,700 mg/kg body weight once daily for 28 days. RESULT: In acute toxicity study no treatment related death or toxic signs were observed. The Long term toxicity study did not show any major toxic signs in the therapeutic dose level, when compared with the control group. CONCLUSION: The trial drug Adathodai Chooranam is safe in the dose of 1.5 g for human adult mentioned in the siddha literature.