Objective To observe the clinical inhibition of circulating tumor cells(CTCs) in differentiated thyroid carcinoma(DTC) by the extract of scabrous patrinia root(Huikangling).Methods Eighty-seven DTC patients tested positive for CTCs were randomly divided into two groups; all patients were treated with oral levothyroxine sodium in accordance with the DTC endocrine inhibition treatment criteria. Patients(n = 45) in the treatment group were provided the standard endocrine therapy along with oral Huikangling(0.4 g/tablet, 0.4 g × 3/time, 3 times/day, 12 weeks). Patients(n = 42) in the control group were only provided the standard therapy. After 4 and 12 weeks, CTCs in the blood were detected by flow cytometry.Results After 4 weeks of oral Huikangling treatment, CTCs were detected in 18(40%) and 29(69%) patients in the treatment and control groups, respectively; the difference was statistically significant(χ2 = 8.49, P < 0.05). After 12 weeks, CTCs were detected in 7(15.6%) and 17(44.7%) patients in the treatment and control groups, respectively; the difference was statistically significant(χ2 = 5.68, P < 0.05). Follow-up evaluation revealed two patients with lung metastasis and one patient with bone metastasis in the control group; one patient showed lateral neck lymph node metastasis without local recurrence in the treatment group.Conclusion Huikangling treatment reduces the number of CTC-positive DTC cases; however, further studies are needed to elucidate the underlying mechanisms. Objective To observe the clinical inhibition of circulating tumor cells (CTCs) in differentiated thyroid carcinoma (DTC) by the extract of scabrous patrinia root (Huikangling). Methods Eighty-seven DTC patients tested positive for CTCs were differentiated into two groups; all patients were treated with oral levothyroxine sodium in accordance with the DTC endocrine inhibition treatment criteria. Patients (n = 45) in the treatment group were provided the standard endocrine therapy along with oral Huikangling (0.4 g / tablet, 0.4 g × 3 / time, 3 Patients were given the standard therapy. After 4 and 12 weeks, CTCs in the blood were detected by flow cytometry. Results After 4 weeks of oral Huikangling treatment, CTCs were detected in 18 (40%) and 29 (69%) patients in the treatment and control groups, respectively, the difference was statistically significant (χ2 = 8.49, 15.6%) and 17 (44.7%) p atients in the treatment and control groups, respectively; the difference was quite significant (χ2 = 5.68, P <0.05). Follow-up evaluated revealed two patients with lung metastasis and one patient with bone metastasis in the control group; one patient showing lateral neck lymph node metastasis without local recurrence in the treatment group. Conclusions Huikangling treatment reduces the number of CTC-positive DTC cases; however, further studies are needed to elucidate the underlying mechanisms.