Tamiflu can cause vomiting, nausea, and even hallucinations. But experts say it’s effective in reducing flu symptoms and is worth the side effects.

Sometimes a cure is worth the side effects. The flu antiviral Tamiflu might be a good example.

In a nasty flu season, Tamiflu is a powerful weapon, say experts. This go-to antiviral works well for the most part, the experts say, typically lessening flu severity and duration.

But it’s also sometimes known to have side effects, such as nausea and vomiting.

Due to a more aggressive H3N2 flu strain, this year’s flu is already taking a toll. At least 30 children have died so far, according to the Centers for Disease Control and Prevention (CDC). And more people are being hospitalized than usual.

The flu has also quickly spread to every state in the United States, except Hawaii.

“This strain is hitting harder,” Dr. Shilpi Agarwal, a family physician in Washington, D.C., told Healthline. “Youngsters less than 6 months old and the elderly are especially hard hit.”

Given these consequences, taking Tamiflu at the first signs of flu is important, say experts.

It’s not that side effects don’t matter.

Common reactions such as nausea and vomiting should be flagged.

Rarer ones like hallucinations in children have also sprung up. One 6-year-old girl in Texas began hallucinating after taking Tamiflu earlier this month, and even tried to jump out of a window.

Skin sensitivity in adults has also been reported.

Still, experts say, the benefits of taking Tamiflu far outweigh the risks.

Tamiflu helps block the flu virus, stopping it from progressing if taken within 48 hours after experiencing symptoms.

“Tamiflu is really important,” Dr. John Shufeldt, an emergency room physician in Arizona, told Healthline. “It lessens duration of the flu by about a day and lessens severity 10 percent to 30 percent.”

Tamiflu may also reduce risk complications, such as ear infections in children and pneumonia and hospitalization in adults, says the CDC.

Kids are especially prone to the effects of flu, Dr. Norina Ocampo, a pediatrician with Tenet Florida Physician Services, told Healthline.

“Their immune systems aren’t as developed — especially under 5,” she said. “They can have higher fatality rates and hospitalization just like people 65 and older.”

She adds that most children don’t have side effects from Tamiflu.

For anyone, being sick longer can lead to a compromised immune system that may spawn lethal bacterial infections, such as pneumonia.

Dr. William Schaffner, a preventive medicine and infectious disease expert at Vanderbilt University School of Medicine, told Healthline that there’s another important reason to use Tamiflu.

It can help stop outbreaks in nursing homes, since the flu can spread quickly — and be more deadly.

Some Tamiflu side effects like confusion or delirium are concerning, says Schaffner.

But, he adds, most of these cases have been reported in Japan, where Tamiflu is used in higher doses for longer time spans.

A doctor should be alerted right away if these symptoms pop up, says the U.S. Food and Drug Administration (FDA).

Also, there’s no medication that doesn’t have some risk, Schaffner notes.

“So every time we do anything therapeutically,” he said, “there’s a risk-benefit analysis.”

Still, don’t ignore side effects such as vomiting, say experts.

“We should take them seriously,” said Agarwal. “At first warning signs, stop taking it.”

Dehydration, for example, can be worse for someone who’s already sick.

“My concern is that people aren’t aware of the side effects,” she added. “It’s about being educated.”

Sometimes side effects can also be erroneously tied to the flu, whose hallmarks are fever or chills. But vomiting, for example, isn’t a common flu symptom, experts add.

Since Tamiflu is in both pill and liquid form, sometimes just changing the Tamiflu formulation helps ease any problems.

“Kids can keep different formulations down better,” Ocampo said.

One of her patients vomited capsules up, but successfully used the liquid form.