Gas‐bubble behavior in a liquid flowing inside a circular tube subjected to an acoustic pressure field is studied analytically and experimentally. Consideration is given to both viscous fluids and whole blood, with the effects of acoustic radiation and viscosity taken into account. Slug flow and laminar parabolic flow cases are treated. Analytical solutions are obtained which predict the trajectory of bubble motion and the location where the bubble can be brought to a standstill on the tube wall by the acoustic force. It is disclosed that the trajectory is strongly dependent upon the acoustic pressure amplitude, flow velocity, and liquid viscosity. By either increasing the acoustic pressure amplitude or decreasing the flow velocity or liquid viscosity, the bubble can be brought to a standstill in the first half‐wavelength from the tube entrance, at the node or antinode depending upon its size. The theory is in good agreement with experiments performed in water and SEPARAN AP30 polymer solutions. The latter fluids resemble whole blood in rheological properties.