Every year, doctors prescribe millions of antibiotics. But about a third of the antibiotics prescribed in doctors’ offices are unnecessary, according to a report released earlier this year by the Centers for Disease Control and Prevention.

Unless an infection is caused by bacteria—which is usually not the case—the drugs will have no effect.

“All antibiotics can have serious side effects, so when they are used inappropriately it’s all risk and no benefit,” says Marvin M. Lipman, M.D., Consumer Reports’ chief medical adviser. “And every time an antibiotic is used, whether its use is indicated or not, there is always a chance of causing bacterial resistance so that it becomes useless in the future.”  

Doctors know that, but they often prescribe antibiotics anyway—in part because patients expect it. That’s starting to change.

As part of the national Choosing Wisely initiative, physician societies have examined the medical evidence and named several common conditions that you should discuss carefully with your doctor before taking antibiotics.

Consumer Reports, a partner in this effort, has created materials that help you have a conversation with your physician.

Here are six conditions you should question your doctor about before taking antibiotics:

1. Respiratory Infections

Colds, the flu, and most other respiratory infections are caused by viruses, which generally can’t be wiped out by antibiotics. Bronchitis is usually caused by a virus or an irritant in the air, such as cigarette smoke.

Consider antibiotics if a cough doesn’t get better in 14 days, or if the doctor diagnoses a bacterial illness, such as strep throat.

Instead, ease symptoms by drinking plenty of liquids, breathing moist air, gargling with salt water, and taking acetaminophen (Tylenol and generic) or ibuprofen (Advil and generic).

2. Sinus Infections

Sinusitis is almost always caused by a virus. Symptoms include a stuffy or runny nose and pain in the face.

Even when bacteria are the cause, the infections usually clear up on their own in about a week.

Consider antibiotics only if you don’t get better after 10 days, if you get better and then worse again, or if you have a high fever and thick, colored mucus for three or more days in a row.

In the meantime, to loosen mucus and help it drain, drink warm liquids; breathe warm, moist air; and keep your head propped up when you lie down.

3. Ear Infections

Most ear infections improve on their own in two or three days, especially in children ages 2 or older.

Give your child over-the-counter pain relievers for a few days, and avoid antibiotics. Visit a doctor if symptoms aren’t better in two to three days or if they worsen.

Get antibiotics right away for babies 6 months or younger, for children from 6 months to 2 years old experiencing moderate to severe ear pain, and for children 2 years or older experiencing severe pain.

4. Pinkeye

Pinkeye (conjunctivitis) is usually caused by a virus or allergy, so antibiotics won’t help. Even bacterial pinkeye usually goes away on its own within 10 days.

Consider antibiotics for bacterial pinkeye if you have a weak immune system, if the condition doesn’t get better in a week without treatment, or if the eye is very swollen or painful or develops a thick, puslike discharge.

Soothe pinkeye symptoms with a clean, cool, wet compress. Pinkeye resulting from allergies can be helped with antihistamine eyedrops.

5. Urinary Tract Infections in Older People

Doctors often find bacteria in routine urine tests and then prescribe antibiotics even when patients have no symptoms of a urinary tract infection (UTI). But older people often have bacteria in their urine with no UTI.

Consider antibiotics only when UTI symptoms, such as pain or burning during urination or a strong urge to go often, are present as well.

6. Eczema

Eczema causes dry, itchy, red skin. Doctors may try to control it with antibiotics. But antibiotics don’t help the itching, redness, or severity of the condition.

To control eczema, moisturize your skin and avoid things that irritate it. Ask your doctor about a medicated cream or ointment to relieve itching and swelling.

Consider antibiotics only if there are signs of a bacterial infection, such as bumps full of pus, honey-colored crusting, very red or warm skin, or a fever.