Abstract: A method of high-flow microinfusion which provides convection-enhanced delivery of agents into the brain and other solid tissue structures. The method involves positioning the tip of an infusion catheter within a tissue structure and supplying an agent through the catheter while maintaining a pressure gradient from the tip of the catheter during infusion. Agent delivery rates of 0.5 to 15.0 .mu.l/min have been used experimentally with infusion distances greater than 1 cm from the delivery source. The method can be used to delivery various drugs, protein toxins, antibodies for treatment or imaging, proteins in enzyme replacement therapy, growth factors in the treatment of various neurodegenerative disorders and viruses and gene therapy. An infusion catheter developed for the high-flow microinfusion includes a plurality of elongated slits adjacent a tapered portion of the catheter which are parallel to the axis of the catheter and spaced symmetrically about the circumference thereof.