The free electron laser (FEL) is a unique laser which is tunable over a wide segment of the spectrum. Its tunability can open a wide range of applications in medicine - both surgical and diagnostic. A delivery device such as a waveguide or a fiber, flexible enough, which will be coupled to its outlet, will enable maneuvering the beam conveniently at the operating site. The greatest obstacle for such a fiber or waveguide is the high peak power of several MWatts that characterize the beam and the wide range of wavelengths. Flexible hollow waveguides made of either a fused silica or a Teflon tubing, internally coated with reflecting/refracting layers, were used in experiments at 3 FEL centers in the U.S. A segment of the mid IR spectrum (between 6 and 7 micrometers). Results of the beam shape (both temporal and spatial) and transmission measurements have proven the potential of this waveguide for transmission of FEL radiation.