A catheter suitable for dissolving blockages in tubular tissue provides a combination of low frequency (1-100 Hz) vibratory motion and injection of a lysing agent. The tubular tissue may be veins, arteries, ducts, intestines, or any other blocked body lumen. For vascular thrombi, the catheter may induce a vibrating, stirring action in and around the thrombus in combination with dispensing of a thrombolytic agent, such as urokinase, into the thrombus. An inflatable or expandable member may be provided near a distal tip of the catheter to prevent release of dislodged thrombus.