Legacy AI grade · Sources dated 2026-07-25. Not expert reviewed. Coverage is limited to the listed sources. About the new summary workflow
Astragalus for Common Cold
There is no reliable evidence that astragalus on its own prevents or treats the common cold. The few positive signals come from multi-herb formulas or a special patient group, not from astragalus taken by itself.
Why this grade7-layer evidence engine
This claim earns a Weak (C) grade mainly because the highest-quality evidence is a blank. A 2016 Cochrane systematic review (PMID 27905672) screened 6,080 records and could not find a single randomized trial of oral astragalus used on its own for respiratory infection, so its real-world effectiveness and safety in healthy people remain untested.
The apparent positives are easy to misread. A 2016 meta-analysis (PMID 27145435) of the Yupingfeng formula reported a higher clinical response rate (RR 1.21), but astragalus is just one of three herbs, so the benefit cannot be pinned on astragalus itself. A small 2013 review (PMID 23662131) found fewer infections (RR 0.56) only in children with nephrotic syndrome, a special group that does not generalize to ordinary colds. Both were rated low quality.
Authorities offer no support. The US FDA lists only tragacanth gum as a food additive, not astragalus as a cold remedy, and major clinics (Mayo, Cleveland Clinic, Harvard, NIH ODS) do not address it. Astragalus may also interact with immunosuppressant drugs, so people who are immune-compromised or on such medication should be cautious.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.58
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — | B→C 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status