Lamicel is a synthetic osmotic cervical dilator reported to work within two hours. To evaluate its efficacy and side effects, we conducted a double-blind, randomized clinical trial comparing Lamicel with multiple laminaria for cervical dilation in 219 patients before second-trimester abortion. A single Lamicel produced significantly less initial dilation (two-tailedPvalue = .03) than did multiple laminaria, but the techniques had comparable degrees of difficulty in subsequent dilation to 43 French units (two-tailedPvalue > .05) and rates of achieving dilation of 43 French units with rigid dilators (relative risk 1.0; 95% confidence interval 0.9–1.1). Lamicel removal resulted in a significantly lower rate of bleeding from the os (relative risk 0.3; 95% confidence interval 0.2–0.5). Because of its greater convenience, lower cost per patient, and comparable efficacy, Lamicel appears to be an attractive alternative to multiple laminaria for cervical dilation before abortion at 14–16 menstrual weeks' gestation.