For the flu, most people benefit from a combination of rest, fluids, over-the-counter fever and pain relievers, and, in some cases, a prescription antiviral. What you take depends on how severe your symptoms are, how quickly you act, and whether you’re at higher risk for complications.
Prescription Antivirals and the 48-Hour Window
Prescription antivirals are the only medications that actually fight the influenza virus rather than just masking symptoms. They work best when started within 36 to 48 hours of your first symptoms. Multiple clinical trials show that early treatment shortens the duration of fever and illness in both children and adults. For influenza B specifically, one newer antiviral (baloxavir) reduced the time to symptom improvement by more than 24 hours compared to the older standard (oseltamivir).
If you miss that 48-hour window, antivirals can still help. One trial found that starting oseltamivir as late as 72 hours after symptom onset still shortened illness by about a day compared to no treatment. This is especially relevant for people at higher risk of serious complications: adults 65 and older, children under 5, pregnant women, and anyone with chronic conditions like asthma, diabetes, or heart disease. If you fall into one of those groups, it’s worth calling your doctor even if you’ve been sick for a couple of days.
To get an antiviral, you need a prescription. Many doctors can diagnose flu based on your symptoms during flu season and call in a prescription without requiring an in-person visit, so a telehealth appointment or phone call is often enough.
Over-the-Counter Medications for Symptom Relief
While antivirals target the virus, OTC medications target the misery. The flu typically brings fever, body aches, congestion, cough, and sore throat, and different products address different symptoms.
Fever and body aches: Acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) are the go-to choices. Both lower fever and reduce the muscle aches that make the flu feel so punishing. You can alternate between the two if one alone isn’t keeping your fever down. Never give aspirin to children or teenagers with the flu. Aspirin use during influenza is linked to Reye’s syndrome, a rare but potentially fatal condition that causes dangerous swelling in the liver and brain.
Congestion: Nasal decongestants containing phenylephrine or pseudoephedrine can open up clogged sinuses. Many combination cold-and-flu products bundle a decongestant with a pain reliever and sometimes a cough suppressant. If you go this route, read labels carefully to avoid accidentally doubling up on acetaminophen by taking a combo product and a separate pain reliever at the same time.
Cough: A cough suppressant (dextromethorphan) can help you sleep at night, while an expectorant (guaifenesin) thins mucus so it’s easier to cough up during the day. Some people find a spoonful of honey works surprisingly well for cough, though it should never be given to children under one year old.
Fluids, Rest, and Recovery Basics
Dehydration during the flu sneaks up on you. Fever, sweating, vomiting, and diarrhea all drain fluids faster than usual. Healthy adults typically need around 11.5 to 15.5 cups of total fluid per day under normal conditions, and you’ll need more when you’re sick. Water is fine, but broth and electrolyte drinks are better choices if you’re vomiting or have diarrhea, because they replace both fluid and minerals your body is losing.
Signs you’re falling behind on fluids include dark urine, dry mouth, headache, and dizziness. If you’re not urinating at all, that’s a sign of serious dehydration that needs medical attention. For children, watch for no urine output for eight hours, no tears when crying, or a dry mouth.
Rest isn’t just a nicety. Your immune system does its heaviest work while you sleep, and pushing through the flu by going to work or exercising typically extends how long you feel terrible. Most people start turning the corner after three to five days of fever, though fatigue and cough can linger for a week or two.
Supplements: Zinc and Vitamin C
Zinc and vitamin C are the two supplements with the most research behind them for respiratory illness. Neither is a cure, but both may shave time off your symptoms. Zinc appears to shorten the duration of illness by a few days when started early. Zinc lozenges are the most commonly studied form.
Vitamin C taken daily (around 200 mg, roughly two to three times what you’d get from an orange) may help you feel better about 13 hours sooner during a typical seven-day illness. That’s a modest benefit, and it seems to work better as a daily habit rather than something you start after you’re already sick. The upper safe limit for vitamin C ranges from 400 mg to 2,000 mg per day depending on age, so megadosing offers diminishing returns and can cause digestive issues.
Elderberry supplements are widely marketed for flu, but the evidence is thinner and less consistent than for zinc or vitamin C. They’re generally considered safe for short-term use in adults, but they’re not a substitute for proven treatments.
Warning Signs That Need Immediate Care
Most flu cases resolve on their own, but some develop into emergencies. In adults, get medical care right away if you experience difficulty breathing, persistent chest or abdominal pain, confusion or inability to stay awake, seizures, no urination, or severe weakness. A fever or cough that improves and then suddenly returns or worsens is another red flag, because it can signal a secondary infection like pneumonia.
In children, the warning signs include fast or labored breathing, bluish lips or face, ribs visibly pulling in with each breath, severe muscle pain (a child who refuses to walk), dehydration, or fever above 104°F that doesn’t respond to fever reducers. Any fever in an infant younger than 12 weeks warrants immediate medical evaluation regardless of how mild it seems.