The present invention provides novel [1,2,4]triazole-3-one derivatives having the general formula (I) wherein: Q is  and R1, R2, R3, R4, R5 and R6 are as defined herein or a nontoxic pharmaceutically acceptable salt or solvate thereof which are smooth muscle relaxants and useful in treating disorders responsive to relaxation of smooth muscle such as asthma, irritable bowel syndrome, male erectile dysfunction and urinary incontinence.