The haemostatic effect of two new materials has been compared with surgical gauze and oxidized cellulose using a standardized liver laceration in New Zealand White rabbits. Following excision of a 3 cm2 disc of tissue from the liver, 42 rabbits were randomized to the use of gauze swabs (n = 6), oxidized cellulose (Surgicel) (n = 12), porcine collagen (Medistat) (n = 12) or calcium alginate (Kaltostat) (n = 12) to control the resulting haemorrhage. Blood loss and time to haemostasis were accurately recorded. The absorbable materials were left in situ and animals killed between 2 weeks and 6 months later to examine speed of absorption and resulting adhesions. Calcium alginate stopped bleeding in less than 3 min in all animals compared with a mean (+/- s.e.m.) of 5.7 +/- 0.75 min for porcine collagen, 12.5 +/- 0.9 min for oxidized cellulose and greater than 15 min with gauze (P less than 0.001). Oxidized cellulose and calcium alginate reabsorbed within 3 months leaving a fibrous scar, but a vigorous foreign body reaction was seen with porcine collagen which caused intestinal obstruction in 5 out of 12 animals within 3 months.