The launch of the Swift satellite in late 2004 enabled rapid spectroscopy for a large number of gamma-ray bursts at redshifts, z~1-6. Thanks to their extreme brightness and location within the star forming regions of galaxies, GRBs provide a direct view of the interstellar medium properties on a variety of scales. In this talk I will present the main results from several years of spectroscopic observations, including the distribution of neutral hydrogen column densities and gas metallicities, and abundance patterns. In addition, follow-up observations of the galaxies with Keck, Magellan, and Spitzer allow us to construct the first mass-metallicity relations at z>2.
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