Normal wound healing is a carefully controlled balance of new tissue formation and destructive processes necessary to remove damaged tissue. Within this complex environment there are many points of regulation, which control the biological processes necessary to achieve wound repair. An alteration in any of these processes can result in an imbalance of the biochemical components, which ultimately results in delayed wound closure and the formation of a chronic wound. Therefore, we propose that an effective therapeutic approach would modify this hostile environment and redress this imbalance. In this study we have evaluated the effect of PROMOGRAN in vivo, in patients with venous leg ulcers. Wound fluid samples were collected and analyzed from a number of patients prior to and during treatment with PROMOGRAN. Our results have shown that wounds, which respond to PROMOGRAN treatment, have also shown a decrease in protease activity in the corresponding wound fluid samples. Whilst it is impossible to determine whether this reduction in protease levels is responsible for healing or merely symptomatic of other changes occurring within the wound, we have shown that a decrease in proteolytic activity is concomitant with healing. This study provides clinical evidence that PROMOGRAN can rebalance the chronic wound environment in situ and thereby promotes wound repair.