Sodium fusidate, an antibiotic used in staphylococcal infections, is strongly bound to human serum albumin, competitively with bilirubin. It is given in molar amounts sufficient to occupy a considerable fraction of circulating albumin. In order to avoid a risk of bilirubin encephalopathy, induced by displacement of bilirubin, fusidate should be given with caution to newborn infants, particularly if patients are prematurely born, icteric or acidotic. Fusidate does not interfere with albumin binding of warfarin or diazepam.