AIM: To estimate the antiasthmatic activity of new compounds: SDF-1, SDG-1 and SDG-3. F-1 is a furoxan derivative, G-1 and G-3 are hydroxylguanidine derivatives, SDF-1 is a novel seratrodast derivative connected with F-1, SDG-1 a seratrodast derivative connected with G-1, and SDG-3 a novel seratrodast derivative connected with G-3. METHODS: Firstly, the in vivo antiasthmatic activity was estimated in asthmatic guinea pigs induced by acetylcholine and histamine. Secondly, the in vitro NO releasement of these compounds was determined following the procedures of Griess. Finally, tracheal smooth muscle relexant potency of these compounds was evaluated on trachea of guinea pigs. RESULTS: The in vivo antiasthmatic activity of SDF-1 was more potent than seratrodast (P