Disclosed is a liquid formulation comprising (a) an antibody in an amount of greater than about 50 mg/mL and (b) dimethyl sulfoxide (DMSO) or dimethylacetamide (DMA) in an amount of between about 0.1% to about 50% v/v of the formulation, wherein the formulation has reduced viscosity compared to the same formulation in the absence of DMSO or DMA.