The investigation was conducted on 11 healthy, non-anaemic adolescent girls of 16-18 years of age. A balance study was conducted in two trials of 3 weeks each on low- and high-fibre diets. The high-fibre diet consisted of the low-fibre diet plus 25 g isabgol husk. The mean diet and nutrient intakes of the subjects were approximately the same during both trials. Addition of isabgol (Isphaghula) husk to the low-fibre diet significantly increased the urinary excretion of phosphorus and iron; faecal excretion of calcium, phosphorus and iron; and the serum calcium, phosphorus and iron levels decreased significantly (P < 0.05). The apparent retention of calcium, phosphorus and iron was significantly (P < 0.05) lowered on the high-fibre diet, but the balances of these nutrients were positive. Thus the isabgol does not have a desirable effect on mineral levels.