Disclosed is a stable liquid pharmaceutical formulation comprising a mixture of an anti-α4&bgr;7 (anti-alpha 4 Beta 7) antibody, an antioxidant or chelator, surfactant, and at least one free amino acid, wherein the molar ratio of the surfactant to the anti-α4&bgr;7 antibody is 0.7:1 to 2.0:1. Also disclosed is its use in treatment.