Adding Compound Danshen Dripping Pills (CDP) to conventional therapy was associated with higher reported angina and electrocardiogram (ECG) response rates than conventional therapy alone, according to a review of randomized controlled trials. The pattern was also reported when CDP was compared with nitrate-containing therapy. But the authors say substantial variation between studies and moderate-to-very-low certainty prevent definitive conclusions about efficacy or long-term safety.
What the trials compared
The evidence came from 93 randomized controlled trials involving 10,208 participants. Twenty-six trials with 2,564 participants compared CDP plus conventional therapy with conventional therapy alone. The remaining 67 trials with 7,644 participants compared the CDP combination with nitrates plus conventional therapy. The studies were published between 1997 and 2025, and treatment periods ranged from 14 to 180 days.
Eligible participants had stable angina. The review's main outcomes were reported angina and ECG efficacy, attack frequency and duration, and nitroglycerine consumption; it also examined cholesterol and triglycerides, low-density lipoprotein cholesterol, left ventricular ejection fraction and fibrinogen, along with adverse events. Angina efficacy was a trial-defined response category: more than 80% reduction in attack frequency counted as markedly effective, while a 50% to 80% reduction counted as effective. The overall rate combined those two categories. For analysis, the review used risk ratios for yes-or-no outcomes and mean differences or standardized mean differences when continuous measures used different scales.
The clearest differences were in reported responses
Against conventional therapy alone, 491 of 528 participants receiving CDP plus conventional therapy met the angina-efficacy definition, compared with 365 of 492 receiving conventional therapy alone. That was 93.0% versus 74.2%, with a pooled risk ratio of 1.26 and a 95% confidence interval of 1.19 to 1.33. ECG response was reported in 88.9% versus 66.1%, with a pooled risk ratio of 1.34 and a 95% confidence interval of 1.19 to 1.51. The review rated the angina finding moderate certainty and the ECG finding low certainty.
Measures of attack burden pointed in the same direction, although the results varied greatly between studies. Across eight randomized controlled trials involving 987 participants, angina frequency was lower with CDP plus conventional therapy than with conventional therapy alone. The pooled standardized mean difference was -1.32, with a 95% confidence interval from -1.79 to -0.84, and I-squared, a measure of differences between study results, was 91%. Across seven trials involving 917 participants, angina duration was also lower, with a standardized mean difference of -2.51, a 95% confidence interval from -3.58 to -1.45 and I-squared of 97%. Across four trials involving 365 participants, left ventricular ejection fraction was higher with CDP, with a standardized mean difference of 1.30 and a 95% confidence interval from 0.24 to 2.37, but I-squared was 95%. The review judged the frequency and duration outcomes very low certainty.
The nitrate comparison showed a similar pattern
Against nitrate plus conventional therapy, reported angina efficacy was 91.8% with CDP versus 80.0% with nitrates. The pooled risk ratio was 1.11, with a 95% confidence interval of 1.08 to 1.15. ECG efficacy was 72.3% with CDP versus 53.5% with nitrates, with a pooled risk ratio of 1.35 and a 95% confidence interval of 1.30 to 1.40. In eight nitrate-comparator trials involving 615 participants, angina frequency was lower with CDP; the standardized mean difference was -0.56, with a 95% confidence interval from -0.91 to -0.21 and I-squared of 78%. The angina result was low certainty and the ECG result moderate certainty.
The nitrate-comparator summary also reported lower estimates for total cholesterol, triglycerides, low-density lipoprotein cholesterol, fibrinogen and nitroglycerine consumption with CDP plus conventional therapy, but certainty for these outcomes was very low. Additional analyses reported a lower peak rate-pressure product, with a mean difference of -4572.65 and a 95% confidence interval from -5423.98 to -3721.33, and higher left ventricular ejection fraction, with a mean difference of 6.49 and a 95% confidence interval from 3.11 to 9.87.
The evidence came with important caveats
The two safety comparisons produced different estimates. In the CDP-versus-conventional-therapy analysis, adverse events were reported in 55 of 551 participants, or 10.0%, with CDP and 65 of 548, or 11.9%, with conventional therapy alone. The pooled risk ratio was 0.84, with a 95% confidence interval from 0.60 to 1.18, a difference the review said was not statistically significant. In the nitrate comparison, adverse events were reported in 2.8% of the CDP group and 19.8% of the nitrate group; the pooled risk ratio was 0.16, with a 95% confidence interval from 0.13 to 0.20. The review rated the first safety result low certainty and the second moderate certainty.
Confidence in the findings was also affected by how the evidence was reported. The review used a PROSPERO-registered protocol and said it followed PRISMA 2020. It searched eight electronic databases from inception through May 31, 2026, and manually checked reference lists. Its risk-of-bias assessment covered five areas, including randomization, deviations from intended interventions, missing outcome data, outcome measurement and selective reporting. GRADE, which rates certainty from high to very low, was used to judge confidence in each result.
Of the 93 included trials, 71 raised some concerns and 22 were judged at high risk of bias. Random allocation was often mentioned, but sequence generation, allocation concealment and blinding were frequently described inadequately. No included trial had an identified prespecified protocol or registration. The authors say these methodological limitations, together with heterogeneity, prevent definitive conclusions.
Product reporting was another weakness. None of the 93 trials reported botanical authentication or sufficient extraction and processing information. Only one study reported finished-product characteristics, while 76 reported marker metabolites and 51 reported manufacturer or certificate information. The review said this left open whether the preparations used across trials were sufficiently comparable.
A cautious conclusion
Overall, the authors describe CDP-containing regimens as potentially helpful for symptoms and some functional outcomes and as generally well tolerated during the treatment periods evaluated. They stress that heterogeneity, methodological limitations and moderate-to-very-low certainty prevent a definitive judgment on efficacy or long-term safety, and that treatment-duration analyses do not establish an optimal course. The authors reported support from four named Chinese research and innovation programs, including the Young Elite Scientists Sponsorship Program and the Tianjin Science and Technology Plan Project.
Paper data and sources
Original title: Efficacy and safety of Compound Danshen Dripping Pills as an adjunct to conventional therapy for stable angina pectoris: an updated systematic review and meta-analysis of randomized controlled trials
Authors: Zhao X, Liu Y, Yang L et al.
Journal/Repository: Frontiers in pharmacology
Status: Peer-reviewed
First online: 2026-10-09
DOI: Not available
Original paper · Full text