Treatment Results of Constipation with Chenodeoxycholic Acid
Results
Figure I shows the number of bowel movements for the single patients before and during the 4 weeks oftreatment. In ten gall-stone patients with chronic constipation the administration of a lactose placebo did not produce any remarkable variation. On the other hand, the administration of chenodeoxycholic acid at a dose of 750 mg/day in three divided doses, with meals, produced a significant increase ofbowe1 frequency. One of the patients treated with chenodeoxycholic acid dropped out because of diarrhoea (18 evacuations of liquid stool) during the first week oftreatment.

Three patients treated with CDCA showed a bowel frequency greater than one movemen per day during the first week of treatment. In these patients the number of bowel movements. Although greater than the pretreatment values, decreased during the subsequent weeks of treatment.  In three patients treated with chenodeoxycholic acid no modification of bowel frequency was observed. The stool consistency during treatment is shown in no significant variation was observed in the placebo group.

Discussion
The cholelitholytic treatment of cholesterol gall-stones with chenodeoxycholic acid, although safe and effective, is often inconvenient for the patient since it may induce diarrhoea. The mechanism by which chenodeoxycholic acid induces diarrhoea in gall-stone treated patients is not completely clear since this primary bile acid should be either absorbed or rapidly transformed in the monohydroxy bile acid, lithocholic acid, by the intestinal bacterial flora An explanation could be that the ingested chenodeoxycholic acid is not completely transformed to lithocholic acid in the distal ileum, and, at least in part, it reaches the colon where it induces diarrhoea by promoting water and electrolyte secretion. The cathartic effect of the oral administration of chenodeoxycholic acid could be useful in the management of patients with chronic constipation.

In this study we administered chenodeoxycholic acid at a dose of about 10 mg/kg/day, which is lower than the conventional dosage, for gall-stone dissolution. The observation that some of the patients had diarrhoea, and that some others did not respond to treatment, could suggest the need to determine the most appropriate dose for each patient. Hepner and Hofmann (1973) demonstrated cholic acid to be an effective cathartic agent in patients with chronic constipation, but the long-term consequences of cholic acid administration on bile acid and lipid. metabolism are unknown. On the other hand, the beneficial effect of chenodeoxycholic acidon biliary lipid is welldocumented. Hypertransaminasemia is known to occur in about 10% of the patients treated with the highest doses of chenodeoxycholic acid used for the litholytic effect. This side-effect has been described by several authors (Danzinger et al 1972, Fromm et al 1975, Schoenfield et al 1981, Roda et al 1982) and although its mechanism is still unknown it has been shown not to be associated with consistent changes in liver function. In conclusion, although further studies are needed to determine the role of chenodeoxycholic acid in the treatment of constipation, our results indicate that this dihydroxy bile acid is helpful in the management of some patients with chronic constipation.