This trial is a randomized, double-blind, placebo-controlled parallel-group, multicenter Phase III clinical trial. It is to evaluate the efficacy and safety of Xuanhuang Runtong Tablets in subjects with constipation (Yin-deficiency type) after 4 weeks of treatment.

Inclusion Criteria:

Subjects must meet all of the following inclusion criteria to enter the run-in period:

1. Meeting the diagnostic criteria of traditional Chinese medicine (TCM) constipation;
2. Meeting the TCM syndrome differentiation criteria of constipation with yin deficiency syndrome;
3. Both males and females are eligible, aged between 18 and 70 years old (including 18 and 70);
4. Willing to participate in the trial and sign the informed consent form.

At the end of the run-in period, subjects must meet all of the following criteria to enter the treatment period:

1. Meeting the diagnostic criteria of TCM constipation;
2. Meeting the TCM syndrome differentiation criteria of constipation with yin deficiency syndrome;
3. The number of spontaneous bowel movements in the last week of the run-in period is less than 3.

Exclusion Criteria:

Subjects with any of the following items cannot enter the run-in period/treatment period:

1. Subjects with constipation or severe anal diseases causing defecation disorders diagnosed by researchers due to rectal, colonic organic diseases (such as tumors, inflammatory bowel diseases, intestinal adhesions, colon tuberculosis, etc.);
2. Subjects with constipation caused by central nervous system diseases (such as multiple sclerosis, Parkinson's disease, spinal cord injury, etc.) or muscle diseases (such as amyloidosis, dermatomyositis, etc.) known or identified as being caused by drugs;
3. Subjects with colonoscopy results showing intestinal polyps > 0.5 cm or quantity > 3 (subjects with removed intestinal polyps are not excluded, but those with tubular adenoma accompanied by high-grade intraepithelial neoplasia or those who need to re-examine colonoscopy in the near future are excluded);
4. Subjects who have taken drugs for treating constipation within 1 week before screening or within 5 half-lives (calculated according to the longer time);
5. Subjects with severe heart, liver, kidney, brain, blood, metabolic and endocrine system diseases and unstable conditions requiring drug adjustment at any time, and patients with malignant tumors;
6. Subjects who are evaluated by researchers as unable to cooperate with clinical trialists in terms of psychological, mental status or cognitive ability, language expression ability, etc. or have a history of severe mental illness, such as patients with severe depression and severe anxiety.
7. Subjects who have had abdominal surgery within 3 months before screening or plan to have abdominal surgery during the trial period;
8. Subjects with HbA1c > 8.5% at screening;
9. Subjects with ALT or AST ≥ 1.5 times the upper limit of the normal value, or Scr > the upper limit of the normal value;
10. Subjects with known or suspected allergies or severe adverse reactions to the components of Xuanhuang Runtong Tablets or Bisacodyl Enteric-coated Tablets, or with an allergic constitution (such as allergies to two or more drugs or foods);
11. Subjects who have participated in other clinical trials and taken trial drugs within the past 3 months;
12. Subjects with suspected or confirmed history of alcohol or drug abuse;
13. Pregnant or lactating women; or female and male subjects of childbearing potential who are unwilling or unable to take effective contraceptive measures during the trial period;
14. Subjects with other conditions that researchers consider inappropriate to participate in this trial.