Side Effects of Sambucol

Sambucol is a brand of standardized black elderberry extract marketed for cold and flu relief. It's available in the form of syrup and tablets. Traditionally, elderberry has been used topically to treat wounds, as well as taken orally for cold and flu symptoms. The elder plant may possess beneficial anti-inflammatory, antiviral, and anti-cancer effects, according to the University of Maryland Medical Center. Elderberry contains antioxidants that may help protect your cells from damage also.

Sambucol may reduce the duration of colds and flu. (Image: David De Lossy/Photodisc/Getty Images)

How Sambucol Works

Sambucol appears to provide benefits against at least 10 strains of influenza virus, according to a study published in the April 2001 edition of the journal "European Cytokine Network." In addition to exerting its own antiviral effects, Sambucol boosts your immune system so that your body can better fight off pathogens. The study found that Sambucol stimulated inflammatory cytokine production. Cytokines are small proteins that help regulate immune response and play a significant role in boosting immunity.

May Act as a Diuretic

Elderberry may act as a diuretic, which means it may increase fluid loss through increased urine output. It's crucial to drink plenty of fluids to prevent dehydration. Talk to your doctor before taking Sambucol if you have a medical condition that increases your risk of dehydration. Use caution if you are currently prescribed a diuretic medication such as hydrochlorothiazide, bumetanide, furosemide, amiloride or metolazone. Taking Sambucol in addition to diuretic medications may increase your risk of dehydration.

May Lower Blood Sugar

Elderberry may lower blood sugar levels. Use caution if you have diabetes as this effect may increase your risk of hypoglycemia, which is when blood sugar levels fall too low. If you're currently taking blood sugar-lowering medications, taking Sambucol may increase the effectiveness of your medication. Symptoms of hypoglycemia include nausea, rapid heartbeat, hunger, shakiness and sweating.

Other Side Effects

Elderberry may exert laxative effects. Avoid taking Sambucol if you're currently taking a laxative. (Elderberry may interfere with certain medications such has theophylline -- an asthma medication -- and chemotherapy drugs. Because Sambucol stimulates the immune system, you may need to avoid it if you are taking immune-suppressing medication as it may reduce the effectiveness of your medicine.