A series of 418 patients with lacerations of the hands were allocated randomly to a control group or to a group where the injury was treated with povidone iodine before suture. The incidence of infected and imperfectly healed wounds was determined seven days later. As well as the effect of povidone iodine on infection, thirteen other factors were also analysed. The overall infection rate of 5.0% and the 38.5% imperfect healing rate were not significantly affected by povidone iodine treatment, although both were reduced. The figures of four other trials were combined with this trial and this showed a significant effect of povidone iodine treatment. There were no adverse reactions to povidone iodine. It is therefore recommended that hand lacerations should be treated with povidone iodine prior to suture. Other factors found to be significantly important in wound infection or imperfect healing were the condition of the dressing, the part of the hand injured and pain. Patients should be strongly advised to keep their dressing clean and dry.