Can Garlic Cure the Common Cold?

December 19, 2014
Jeannette Y. Wick, RPh, MBA, FASCP

Patients turn to garlic supplements for a number of conditions, one of the most popular being the common cold. The basis for such action is the supposed antimicrobial and antiviral properties of the medicinal plant.

Patients turn to garlic supplements for a number of conditions, one of the most popular being the common cold. The basis for such action is the supposed antimicrobial and antiviral properties of the medicinal plant.

When considering associated medical costs, missed work, and the possibility of severe complications in at-risk groups, the common cold is estimated to cost $40 billion annually in the United States. Therefore, garlic could be an inexpensive way to save billions of dollars if it can prevent colds.

To put the theory to the test, researchers in Austalia completed a meta-analysis on the available evidence on garlic and the common cold. The group looked for randomized controlled trials examining common cold prevention and treatment that compared garlic with placebo, no treatment, or standard treatment.

Although they conducted a comprehensive search, the researchers had difficulty finding studies that met their high standards for inclusion. Ultimately, they found only 8 studies that were potentially relevant, and just 1 study met the inclusion criteria.

In that study, 146 participants were randomly assigned to receive either 180 mg of allicin—garlic’s active compound—or once-daily placebo for 12 weeks. Those in the garlic group reported 24 colds, compared with 65 in the placebo group. However, the researchers noted that the study participants self-reported colds, and no one confirmed a cold by objective observation.

The intervention group also experienced fewer days of illness (111 days) compared with those who took placebo (366 days). Nevertheless, time to recovery from the common cold was similar in both groups, at approximately 5 days.

Since the researchers could only find 1 study that was structured in an acceptable way, they could draw only limited conclusions. As a result, they concluded that garlic may prevent colds, but more well-structured studies are needed to determine whether it is an appropriate preventive measure.