Hydrocolloid dressing. The gloved hands of a medical worker apply a hydrocolloid dressing called Granuflex to the leg of a patient. Hydrocolloid dressings are flexible dressings made of an adhesive, gum-like material such as pectin, covered with a water resistant film. This dressing keeps the wound surface moist and is particularly useful in the treatment of ulcers. It should not be used on wounds that are infected.