Leg ulcers are a common, costly and debilitating condition with few proven treatment options. Compression therapy (tight bandaging or stockings) helps healing, but a significant proportion of people with venous leg ulcers remain unhealed after 12 weeks of treatment. Standard dressings do not influence wound healing, but some special dressings may increase healing when used in addition to compression in people with slow healing venous leg ulcers. Research suggests New Zealand wool-derived keratin dressings (Keramatrix) may be just such a dressing, increasing keratinocyte migration and initiating venous ulcer healing. However, the current evidence is not sufficient to change clinical practice. The randomised controlled trial we propose will test whether using Keramatrix increases healing and improves quality of life, without increasing adverse events. If it does, Keramatrix is a treatment that could quickly be put into clinical practice in New Zealand and internationally.