Compounds and methods are provided for modulating in vitro and in vivo processes mediated by selectin binding. More specifically, selectin modulators and their use are described, wherein the selectin modulators that modulate (e.g., inhibit or enhance) a selectin-mediated function comprise a class of compounds termed BASAs (Benzyl Amino Sulfonic Acids, which include a portion or analogue thereof linked to a carbohydrate or glycomimetic.