One hundred consecutive patients were prospectively studied to assess the clinical and biochemical features of symptomatic choledocholithiasis. Biochemical tests were performed during the three days following the onset of symptoms. Pain was the most frequent symptom of choledocholithiasis, observed in 75% of the patients, but rarely occurred alone (12%). Clinical symptoms were not different according to age. High serum gamma glutamyl transpeptidase and alkaline phosphatase were the most frequent biochemical abnormalities in patients with symptomatic choledocholithiasis: they were increased in 94 and 91% of cases, respectively. Only one patient had no biochemical abnormality. Serum transaminases could reach very high levels just as in hepatitis. Biochemical data did not differ regardless of whether the common bile duct was enlarged or not. Biochemical abnormalities had been studied over the first 10 days of spontaneous evolution in 25 patients while choledocholithiasis persisted: serum bilirubin and transaminases significantly decreased while serum gamma glutamyl transpeptidase, alkaline phosphatase, and amylase remained unchanged. These results indicate that, in patients with suggestive symptoms, choledocholithiasis is unlikely in the absence of biochemical abnormalities in the first three days following the onset of symptoms.