D-Penicillamine alters the normal metabolism of collagen by inhibiting cross-linking and protein synthesis. This could affect wound healing, accelerate skin thinning and possibly exaggerate the osteoporosis of rheumatoid disease. The mean time to wound healing after 42 orthopaedic surgical operations in 21 patients treated with penicillamine was 19.8 (+/- 13.1) days. Compared with an earlier study, these results suggest that the drug has a comparable effect on would healing to corticosteroids given for three years. Skinfold thickness over the fourth metacarpal of the dominant hand was measured in 28 cases before and during penicillamine treatment. There was a significant decrease both in the first and second four-month periods of treatment (P less than 0.005 and P less than 0.01). Corticosteroids in constant dose did not have an additive effect. In view of the wound healing findings the significance of these results must await further sequential measurements. The normal progression of osteoporosis over three years was documented in 70 patients who had not received penicillamine. Penicillamine reversed this trend in 35 patients after one year of treatment (P less than 0.005). The results confirm that the osteoporosis is related to disease severity rather than drug therapy.