Glucose is a common component of body fluids. We describe a hydrogel wound dressing that can be obtained by pouring an aqueous solution of a polyvinyl alcohol derivative possessing phenolic hydroxyl moieties (PVA-Ph), containing glucose oxidase (GOx) and horseradish peroxidase (HRP), onto a wound. The in situ hydrogelation progresses through GOx-catalysed hydrogen peroxide (H2O2) generation from glucose in the wound exudate and HRP-catalysed cross-linking between phenolic hydroxyl moieties in PVA-Ph by consuming the H2O2. The potency as a wound dressing is demonstrated by experiments which reveal that the existence of the conditions inducing hydrogelation within 20 s at normal blood glucose concentration, the durability of the resultant hydrogels to compression and stretching, and the faster closure of full-thickness wounds created on rats treated with the in situ formed hydrogel than those treated by a commercially available hydrogel dressing.