Quinazolines are versatile nitrogen heterocyclic compounds displaying a broad spectrum of biological and pharmacological activities. The influence of some new synthesized quinazolines with axial and central chirality was studied on the isometric muscle tension of rat ileum, rat uterus, and porcine coronary artery. While structural changes of the compounds showed only little influence on peristaltic movement of the ileum, quinazoline derivatives induced a relaxation in the uterus and in the coronary artery depending on the kind and position of the substituent. The introduction of axial chirality into the molecule of modification of the side chain caused an increase in the pharmacological action. These effects could not be inhibited by sympatholytics. So far the mechanisms and receptors causing the spasmolysis are unknown.