The treatment of necrotic ulcers involves considerable nursing time and expense. The current standard treatment involves repeated application of hydrogels. Larval debridement therapy (LDT) has been shown anecdotally to clear ulcers of necrotic slough but has never been compared directly with 'modern' therapies. The aim of this study has been to compare LDT with hydrogel dressings in the treatment of necrotic venous ulcers. 12 patients with sloughy venous ulcers were randomised to receive either LDT or the control therapy--a hydrogel. Effective debridement occurred with a maximum of one larval application in 6/6 patients. 4/6 patients [corrected] in the hydrogel group still required dressings at one month. The median cost of treatment of the larval group was 78.64 Pounds compared with 136.23 Pounds for the control treatment group (p < 0.05). The study confirms both the clinical efficacy and cost effectiveness of larval therapy in the debridement of sloughy venous ulcers.