Invention of foam sclerotherapy has significantly changed the current phlebological practice. Compared with liquid sclerosants, obliterating foam is more efficient, especially for the closure of larger veins. This review discusses clinical aspects of foam sclerotherapy with a focus on its use for the treatment of venous leg ulceration, including the rationale for its use in the treatment of these chronic wounds, physicochemical mechanisms responsible for stability and disintegration of sclerosant foam, pathomechanism of neurologic adverse events seen after foam sclerotherapy, and techniques that can increase efficacy of this procedure and lower frequency of adverse events.