A physician's review of Echinacea clinical studies contains good news for the treatment of colds. The review reaffirms conclusions from previous peer-reviewed research – Echinacea is safe and can work in the early treatment of acute upper respiratory infections, such as colds.

Echinacea is a perennial herb from the composite or aster family that contains flowers such as daisies and sunflowers. It grows wild throughout the central plains of the United States and was used by Native Americans. It has gained increasing popularity in Europe as a treatment for respiratory and urinary tract infections. Extracts from the plant's leaves, flowers, or roots are used in preparing commercial products.

The review, published in the August issue of The Journal of Family Practice, examined the evidence from 13 clinical trials. In each trial, patients were randomly assigned to receive a placebo or Echinacea. The studies were double-blinded, so neither patients nor physicians knew the assigned substance.

Nine of the 13 clinical trials examined the use of Echinacea in treating respiratory infections and eight reported positive results. Typically, patients began treatment with the first signs of infection, and treatment continued for eight days. Compared with placebo groups, the groups taking Echinacea reported fewer "full blown" colds, milder symptoms if a cold developed, or colds of shorter duration. In the minds of most consumers, this probably would be viewed as "prevention." A lower dose of Echinacea was used in the one study that showed no beneficial effect, which might account for the negative findings.

The other four studies were trials of chronic use in the absence of symptoms and all reported some benefit from Echinacea. In these studies, the participants took a placebo or Echinacea for a longer period, typically two to three months. While all four studies reported positive results, they were not all statistically significant.

Additional research – with a larger number of participants and more objective measurements for outcome – should further clarify the value of Echinacea in preventing respiratory infections. Based on the current research, the physician authors concluded, "the evidence suggests Echinacea taken early in the course of an illness may be safe and effective in reducing the severity and duration of the common cold."

Source: Council for Responsible Nutrition, CRN News, September 1999.