Abstract: The monopotassium salt of 14-Deoxy-11, 12-didehydroandrographolide-3,19-disuccinate (DAS) neutralized with equivalentamount of sodium bicarbonate is an aqueous soluble preparation derived from andrographolide which is the principal composition of Andrographis paniculata Ness. DAS was reported to have therapeutic effect on pneumonia and upper respiratory tract infection of virus origin. We investigated its anti-inflammatory activity in mice and rats. The experimental results showed that DAS significantly inhibited the increase of capillary permeabilities induced by various phlogistic stimulations and exudation induced by croton oil, but had no effect on granuloma formation around cotton pellet or in granuloma pouch. DAS was found to inhibit egg-white induced edema of the hind paw in intact rats but not in adrenalectomized animals. DAS induced marked involution of the thymus in immature mice and significantly depleted the content of adrenal ascorbic acid of rats. However, this action of DAS was abolished by hypophysecton(?)y. After five consecutive daily injections of DAS the ACTH content of the pituitary gland some increased with significant depletion of adrenal ascorbic acid content in rats. These results indicate that the anti-inflammatory activity of DAS is presumably due to increasing synthesis and release of ACTH of the pituitary gland.