There is evidence that psychological stress adversely affects the immune system. We have investigated the effects of such stress, caused by caring for a relative with Alzheimer's disease, on wound healing. We studied 13 women caring for demented relatives (mean age 62.3 [SE 2.3] years) and 13 controls matched for age (60.4 [2.8] years) and family income. All subjects underwent a 3.5 mm punch biopsy wound. Healing was assessed by photography of the wound and the response to hydrogen peroxide (healing was defined as no foaming). Wound healing took significantly longer in caregivers than in controls (48.7 [2.9] vs 39.3 [3.0] days, p < 0.05). Peripheral-blood leucocytes from caregivers produced significantly less interleukin-1 beta mRNA in response to lipopolysaccharide stimulation than did controls' cells. Stress-related defects in wound repair could have important clinical implications, for instance for recovery from surgery.