The chief herb, fu ling, strengthens spleen qi and thus its transforming and transporting functions, and leaches out dampness. The deputy, gui zhi, warms the yang, dispels cold and resolves congested fluids. So gui zhi enhances the ability of the chief herb to leach out dampness. Bai zhu, the assistant herb, augments the transformative and transportive function of the spleen and leaches out dampness. Zhi gan cao, the envoy, tonifies the middle qi and harmonizes the function of the other herbs. So the main functions of this formula is to warm the middle burner and expel congested cold fluids.