The goal of this clinical trial is evaluating the efficacy and safety of Lianxiaxiaopi Granules in participant population. The main questions it aims to answer are:

1. Based on the Response rate of postprandial distress syndrome participants, evaluate whether the efficacy of Lianxiaxiaopi Granules is superior to placebo.
2. Evaluate the efficacy of Lianxiaxiaopi Granules in improving symptom of postprandial distress syndrome.
3. Evaluating the safety of Lianxiaxiaopi Granules in postprandial distress syndrome participants.

Inclusion Criteria:

1. Age 18 to 65 years old (including boundary value), gender is not limited;
2. meet the diagnostic criteria for postprandial distress syndrome (Rome IV.);
3. Meet the syndrome differentiation standards of Traditional Chinese Medicine for cold and heat miscellaneous syndromes;
4. NRS score of at least one symptom of postprandial distress syndrome (postprandial fullness, discomfort, early satiety) in the screening period and baseline period≥ 4 points; and did not have moderate/severe epigastric pain syndrome (mid-epigastric burning sensation and mid-upper quadrant pain both < 4 points);
5. Those who did not have organic abnormal changes in the results of gastroscopy (including no abnormalities in gastroscopy, chronic non-atrophic gastritis/chronic superficial gastritis with erythema grade I and/or erosion that was flat and only grade I);
6. Negative Helicobacter pylori test in 13C/14C breath test during the screening period;
7. Voluntarily participate in clinical trials, sign informed consent, and understand and comply with research procedures.

Exclusion Criteria:

1. Those who have undergone Helicobacter pylori eradication treatment within 6 months before screening;
2. Gastric mucosal erythema grade II or above, erosion is bulge or grade II or above, or accompanied by bleeding, bile reflux, ≥ 3 inflammatory polyps and other manifestations, or combined with pathological diagnosis of chronic atrophic gastritis, hyperplastic polyps, glandular polyps, etc.; or those who have been clearly diagnosed with dyspepsia caused by organic diseases of the digestive system, such as digestive tract tumors, hepatobiliary and pancreatic diseases, inflammatory bowel diseases, etc.; or those who have other diseases that affect the evaluation of dyspepsia-related symptoms in the past, such as reflux esophagitis, peptic ulcer, gastrointestinal bleeding, intestinal obstruction, etc.;
3. Those who have been diagnosed with systemic diseases that seriously affect the function of the digestive tract, such as hyperthyroidism or hypothyroidism, diabetes, chronic renal insufficiency, connective tissue diseases, etc.;
4. Patients with severe cardiovascular and cerebrovascular, liver, lung, kidney, blood or systemic diseases that affect their survival; or patients with severe mental illness in the past, such as moderate or severe depression/anxiety/bipolar disorder, etc.;
5. Those who have a history of major abdominal surgery in the past, which may affect gastrointestinal function (except for appendectomy, cesarean section, endoscopic colon polyp resection and other surgeries that do not affect digestive function);
6. Patients with abnormal liver function (ALT or AST >1.5 times the upper limit of normal) or abnormal renal function test (Cr> upper limit of normal);
7. Glycosylated hemoglobin ≥ 6.5% or fasting blood glucose ≥7mmol/L during the screening period;
8. Use of drugs or treatments that may have an impact on the effectiveness assessment of the trial drug within 2 weeks before screening (such as acid/antacids, gastrointestinal motility drugs, digestive enzymes, gastric mucosal protectors, antiemetics, antispasmodics, macrolide antimicrobials, azole antifungals, non-steroidal anti-inflammatory drugs, glucocorticoids, anti-anxiety and depressants, analgesics, sedatives; as well as traditional Chinese medicine decoctions, proprietary Chinese medicines and acupuncture treatments for the treatment of functional dyspepsia, etc.);
9. Pregnant and lactating women, who have a birth plan within one month after enrollment and the end of the trial;
10. Those who suspect or have a history of alcohol or drug abuse;
11. Participated in other clinical trials within 1 month before screening;
12. Those who are suspected or known to be allergic to the ingredients of this medicine;
13. According to the judgment of the investigator, it is not suitable to participate in this study.