The Food and Drug Administration is warning consumers to be on the lookout for unapproved products that claim to prevent or treat the flu.

With flu season in full swing, the Food and Drug Administration (FDA) has released a warning to consumers to be wary of unapproved flu products.

The agency reminded consumers in a statement earlier this month that “there are no legally marketed over-the-counter drugs to prevent or cure the flu.”

There are some legal over-the-counter products that may relieve congestion, muscle aches, and other symptoms that typically come with the flu.

However, there aren’t any products that cure the ailment.

Unproven flu claims include statements such as “reduces severity and length of the flu,” “prevents catching the flu,” and “supports your body’s natural immune defenses to fight off the flu.”

Relying on these products not only can waste your money, but they may also delay you in getting prompt medical care for flu or flu-like symptoms.

The FDA also warns about online pharmacies selling prescription antiviral drugs, such as Tamiflu, without a prescription. These are often counterfeit or unapproved drugs.

Here are five fake “flu products” to keep an eye out for.

Some may be sold by themselves or as an ingredient in a “flu-busting” formula.

This is a homeopathic remedy made from wild duck heart and liver that’s marketed as relieving influenza-like symptoms.

Homeopathy is based on “curing like with like,” often with substances diluted until they can no longer be detected.

A 2015 review of previous medical studies found that there wasn’t enough evidence to show that Oscillococcinum can be used to prevent or treat flu or flu-like symptoms.

The Federal Trade Commission (FTC) also recently announced in a statement that “homeopathic product claims are not based on modern scientific methods and are not accepted by modern medical experts.”

This product, scientifically called Bursera graveolens, is also known as “holy wood” or “holy stick.”

It’s a wild tree native to Mexico, Peru, and Venezuela.

It’s sometimes used in folk medicine for stomachache, rheumatism, and other conditions.

Some companies now promote the use of palo santo essential oil to reduce cold and flu symptoms by improving your blood circulation and increasing your energy levels.

A few studies have looked at palo santo but not for treating cold or flu.

None of these were randomized clinical trials, the gold standard for determining if a medical treatment works.

This product has long been touted as having antiviral, antibacterial, and anti-fungal properties.

Some websites claim that in order to “dissolve the lipid coating of the flu virus” and kill it, you have to mix colloidal silver with wine and lemon juice.

Colloidal silver consists of small silver particles in a liquid.

Researchers have been investigating using silver nanoparticles for medical uses such as killing bacteria in skin wounds.

But no high-quality studies have shown that taking colloidal silver by mouth can treat or prevent the flu, or provide any other health benefits.

In fact, taking colloidal silver can lead to a permanent bluish-gray discoloration of the skin known as argyria.

Colloidal silver can also interfere with certain antibiotics and other medications.

This natural ingredient is often marketed as a treatment for colds.

One study, now withdrawn, found that taking zinc by mouth within 24 hours of the start of cold symptoms may reduce the severity and duration of a cold.

These studies, though, were done with the cold virus, which is different from the virus that causes the flu.

So far, no studies have shown that zinc can prevent or treat the flu.

Oral zinc can also cause side effects such as nausea, upset stomach, or copper deficiency. It may also interact with antibiotics or other medications.

Use of zinc nasal sprays has been linked to a permanent loss of smell.

Zinc does play a role in supporting the immune system, which is why some doctors recommend taking regular supplements.

This may be more important for vegetarians, since their diet often lacks zinc-rich foods.

This natural product has been touted as a prevention or treatment for the common cold.

A 2013 review found that taking vitamin C regularly may, in fact, shorten cold duration. But it doesn’t work if you start taking vitamin C once you have a cold.

As with zinc, these studies were done with the common cold, so it may not have the same effect on the flu.

In 2008, the makers of the Airborne herbal and vitamin formula settled a lawsuit for falsely advertising that the product could prevent colds.

Now the company markets Airborne as an “immune booster,” which is vague enough not to draw the attention of the FDA.

Like zinc, vitamin C plays an important role in immune function. However, this doesn’t mean these can prevent the flu — even if a company markets a product containing zinc or vitamin C as an “immune booster” or an “immune support supplement.”

Only high-quality randomized controlled trials can show what works — and what doesn’t — to prevent or treat the flu.