Thirty patients with radiolucent stones in a radiologically functioning gall bladder were treated for up to two years with a combination of Rowachol (one capsule twice daily), a mixture of cyclic monoterpenes, and chenodeoxycholic acid (7.0-10.5 mg/kg/day). The patients were not selected for body weight or size of stones. All complete dissolutions diagnosed by oral cholecystography were confirmed or refuted by ultrasound examination. Control of symptoms was excellent, only one patient withdrawing from the study because of persistent biliary pain. No evidence of hepatotoxicity was detected biochemically, and diarrhoea due to chenodeoxycholic acid was minimal at this dose. Stones disappeared completely in 11 patients (37%) within one year and in 15 (50%) within two years. These results compared favourably with those obtained with similar doses of chenodeoxycholic acid alone, in particular those of the National Co-operative Gallstone Study (complete dissolution in 13.5% of patients at two years). Treatment with a combination of medium dose chenodeoxycholic acid with Rowachol for radiolucent gall stones is economical, effective, and likely to minimise persistent symptoms and adverse effects of treatment.