Compositions comprising macromers having a backbone comprising units having a 1,2-diol and/or 1,3-diol structure for tissue bulking and coating. Such polymers include poly(vinyl alcohol) (PVA) and hydrolyzed copolymers of vinyl acetate, for example, copolymers with vinyl chloride, N-vinylpyrrolidone, etc. The backbone polymer contains pendant chains bearing crosslinkable groups and, optionally, other modifiers. When crosslinked, the macromers form hydrogels having many properties advantageous for use as agents to hulk and coat tissues.