In a prospective double-blind controlled trial the effect of large doses of ascorbic acid on the healing of pressure-sores has been assessed. 20 surgical patients were studied, the pressure areas being assessed by serial photography and ulcer tracings. The mean ascorbic-acid levels in treated and non-treated groups one month after the start of treatment were 65.6 and 25.8 mug per 10-8 white blood-cells. In the group treated with ascorbic acid there was a mean reduction in pressure-sore area of 84% after one month compared with 42.7% in the placebo group. These findings are statistically significant (P less than 0.005) and suggest that ascorbic acid may accelerate the healing of pressure-sores.