We studied the potentially bronhodilatatory action of some new xanthine compounds, theophylline derivatives with 7-[2-hydroxy-3-(4-acetamido)-phenoxy-propyl]-8-R-1,3-dimethyl-xanthine and 8-R-1,3-bis-(1,3-dimethyl-xanthin-7yl)-2-hydroxy-propane structure substituted in 7 and 8 position. The tracheal smooth muscle contraction we realized by carbachol (10(-5) M) or potassium chloride (40 mM), the xanthine compound being much active on the contraction induced by carbachol. We observed that the modification realised in theophylline structure determined the modification of bronchodilatatory properties. The bronchodilatatory effect of theophylline intensified with the introduction in 7 position the 2-hydroxy-3-(acetamido)-phenoxy-propyl and in 8 position the bromo, nitro, piperidinyl and imidazolyl radicals.