The invention provides novel thiocarbamate alpha-4 inhibitors of the general formula (I) wherein L is -C(S)-O- or -C(O)-S-; that are resistant to metabolism having improved half-life and/or clearance properties compared to corresponding carbamate compounds wherein substituents L, X, Y, Z, R1-R4, m, n, o and p are as defined herein. Also provided are compositions comprising compounds of formula I and a carrier, diluent or excipient as well as methods of treating a disease or condition mediated by the binding interaction of alpha-4 integrins to its ligands such as inflammatory diseases.