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