Complementary and alternative medicine therapies for the common cold
| INTERVENTION | EVIDENCE FOR PREVENTION (LEVEL*) | EVIDENCE FOR TREATMENT (LEVEL*) |
|---|---|---|
| Echinacea purpurea | No evidence found in 2 RCTs (level IIa)8,9 | Evidence found in 5 of 6 RCTs (level IIa)10–15 |
| Zinc lozenges | No trials evaluate prevention | Evidence found in 5 of 9 RCTs (level IIa)16–24 |
| Vitamin C | Evidence found in meta-analysis of 30 RCTs; more benefit in children and in adults under stress (level I)25 | No evidence found in meta-analysis of 11 RCTs (level I)25 |
| Ginseng | Inconsistent; evidence found in 2 of 4 RCTs (level IIb)26–29 | No trials evaluate treatment |
| Garlic (allicin) | Evidence found in 1 RCT (level IIb)30 | No trials evaluate treatment |
| Probiotics | No evidence found in 4 of 6 RCTs (level IIa)31–36 | No trials evaluate treatment |