Disclosed is a method and system for controlling the formation of liquid or gas slugs along a pipeline. In embodiments, an injection unit injects a liquid surface tension reducing agent, such as a foamant, into the pipeline upstream of the high point. A control unit can be used to control the injection unit. In certain arrangements, the control unit adjusts the injection of the agent based on measured parameters of interest. In embodiments where the control unit utilizes temperature measurements, one or more temperature sensors are positioned along the pipeline. The control unit utilizes the temperature measurements to determine whether a predetermined condition exists or a liquid or gas slug is present.