The common cold is an illness affecting your nose and throat. Most often, it's harmless, but it might not feel that way. Germs called viruses cause a common cold.

Often, adults may have two or three colds each year. Infants and young children may have colds more often.

Most people recover from a common cold in 7 to 10 days. Symptoms might last longer in people who smoke. Most often, you don't need medical care for a common cold. If symptoms don't get better or if they get worse, see your health care provider.

Illnesses of the nose and throat caused by germs are called upper respiratory tract infections.

Most often, common cold symptoms start 1 to 3 days after someone is exposed to a cold virus. Symptoms vary. They can include:

• Runny or stuffy nose.
• Sore or scratchy throat.
• Cough.
• Sneezing.
• Generally feeling unwell.
• Slight body aches or a mild headache.
• Low-grade fever.

The mucus from your nose may start out clear and become thicker and yellow or green. This change is normal. Most often, it doesn't mean that you have a bacterial illness.

When to see a doctor

For adults. Most often, you don't need medical care for a common cold. But see your health care provider if you have:

• Symptoms that get worse or do not get better.
• Fever greater than 101.3 degrees Fahrenheit (38.5 degrees Celsius) that lasts more than three days.
• Fever returning after a fever-free period.
• Shortness of breath.
• Wheezing.
• Intense sore throat, headache or sinus pain.

For children. Most children with a common cold don't need to see a health care provider. Get medical care right away if your child has any of the following:

• Fever of 100.4 degrees Fahrenheit (38 degrees Celsius) in newborns up to 12 weeks.
• Rising fever or fever lasting more than two days in a child of any age.
• More-intense symptoms, such as headache, throat pain or cough.
• Trouble with breathing or wheezing.
• Ear pain.
• Fussiness or drowsiness that isn't typical.
• No interest in eating.

Many viruses can cause a common cold. Rhinoviruses are the most common cause.

A cold virus enters the body through the mouth, eyes or nose. The virus can spread by:

• Droplets in the air when someone who is sick coughs, sneezes or talks.
• Hand-to-hand contact with someone who has a cold.
• Sharing objects with the virus on them, such as dishes, towels, toys or telephones.
• Touching your eyes, nose or mouth after contact with the virus.

These factors can increase the chances of getting a cold:

• Age. Infants and young children have a greater risk of colds than other people, especially if they spend time in child care settings.
• Weakened immune system. Having a long-term illness or weakened immune system increases your risk.
• Time of year. Both children and adults are more likely to get colds in fall and winter.
• Smoking. Smoking or being around secondhand smoke increases the risk of catching a cold.
• Exposure. Being in crowds, such as at school or on an airplane, increases the chance of getting a cold.

These conditions can occur along with your cold:

• Middle ear infection. This is the swelling and build-up of fluids in the space behind the eardrum. It may be caused by a virus or bacteria. Typical signs and symptoms include earaches or the return of a fever following a common cold.
• Asthma. A cold can trigger wheezing, even in people who don't have asthma. For people with asthma, a cold can make it worse.
• Sinusitis. In adults or children, a common cold that lasts a while can lead to swelling and pain in the sinuses. These are air-filled spaces in the skull above the eyes and around the nose. A virus or bacteria may cause sinusitis.
• Other illnesses. A common cold can lead to illnesses of the lungs, such as pneumonia or bronchitis. People with asthma or weakened immune systems have an increased risk of these conditions.

There's no vaccine for the common cold. You can take these steps to slow the spread of the virus and prevent illness:

• Wash your hands. Wash your hands well and often with soap and water for at least 20 seconds. If soap and water aren't available, use an alcohol-based hand sanitizer with at least 60% alcohol. Teach your children the importance of hand-washing. Try not to touch your eyes, nose or mouth with unwashed hands.
• Clean and disinfect. Clean and disinfect surfaces that are touched often. These include doorknobs, light switches, electronics, and kitchen and bathroom countertops. This is especially important when someone in your family has a cold. Wash children's toys often.
• Cover your cough. Sneeze and cough into tissues. Throw away used tissues right away, and then wash your hands. If you don't have a tissue, sneeze or cough into the bend of your elbow, and then wash your hands.
• Don't share. Don't share drinking glasses or silverware with other family members.
• Stay away from people with colds. Avoid close contact with anyone who has a cold. Stay out of crowds when possible. Try not to touch your eyes, nose and mouth when you're in crowds.
• Review your child care center's policies. Look for a child care setting with good hygiene practices and clear policies about keeping sick children at home.
• Take care of yourself. Eat well, exercise and get plenty of sleep to help you stay healthy.

You usually don't need medical care for a common cold. But if symptoms get worse or don't go away, see your health care provider.

Most people with a common cold can be diagnosed by their symptoms. Your care provider may take a nasal or throat swab to rule out other illnesses. A chest X-ray may be ordered to rule out a lung illness.

There's no cure for the common cold. Most cases of the common cold get better without treatment within 7 to 10 days. But a cough may last a few more days.

The best thing you can do is take care of yourself while your body heals. Care tips include:

• Rest.
• Drink plenty of liquids.
• Humidify the air.
• Use saline nasal rinses.

Antibiotics do not treat cold viruses. They are used to treat illnesses caused by bacteria.

Pain relievers

Pain relievers you can buy without a prescription can lessen the discomfort of a sore throat, headache or fever.

For adults. Nonprescription pain relief for adults includes:

• Acetaminophen (Tylenol, others).
• Ibuprofen (Advil, Motrin IB, others).

For children. Guidelines for pain relief medicines for children include the following:

• Do not give children or teenagers aspirin. Aspirin has been linked to Reye's syndrome, a rare life-threatening condition, in children or teenagers who have the flu or chickenpox.
• Use children-strength, nonprescription pain relievers. These include children's acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin, others).
• For children younger than 3 months old, don't use acetaminophen until your baby has been seen by a health care provider.
• Don't give ibuprofen to a child younger than 6 months old or to children who are vomiting frequently.
• Use these medicines for the shortest time possible and follow label directions to avoid side effects.
• Call your health care provider if you have questions about the right dose.

Decongestant nasal sprays

For adults. Adults can use decongestant drops or sprays for up to five days. These help a stuffy nose. Prolonged use can cause the return of symptoms.

For children. Children younger than 6 years old shouldn't use decongestant drops or sprays. Talk to your doctor before using nasal decongestants in children older than 6 years.

Cough syrups

Nonprescription cough and cold medicines are used to treat the symptoms of coughs and colds, not the underlying disease. Research suggests that these medicines don't work any better to treat colds than a placebo, an inactive medicine used in research.

For adults. Follow these tips for nonprescription cough and cold medicines:

• Read and follow the label directions.
• Don't take two medicines with the same active ingredient, such as an antihistamine, decongestant or pain reliever. Too much of a single ingredient could lead to an accidental overdose.

For children. Nonprescription cough and cold medicines aren't typically recommended for children. These medicines have potentially serious side effects, including fatal overdoses in children younger than 2 years old. Talk to your child's doctor before using any nonprescription cough and cold medicine in children.

To make yourself as comfortable as possible when you have a cold, try these tips:

• Drink plenty of fluids. Water, juice, clear broth or warm lemon water are good choices. Avoid caffeine and alcohol, which can increase fluid loss.
• Sip warm liquids. Chicken soup, tea, warm apple juice or other warm liquids can soothe a sore throat and loosen a stuffy nose. Honey may help coughs in adults and children who are older than age 1. Try it in hot tea. Do not give honey to children younger than 1 year old because of the risk of an illness called infant botulism.
• Rest. Rest as much as possible. Stay home from work or school if you have a fever or a bad cough. Do not go out if you are drowsy after taking medicine.
• Adjust your room's temperature and humidity. Keep your room warm, but not overheated. If the air is dry, a cool-mist humidifier can help with stuffiness and coughing. Clean your humidifier as directed to prevent the growth of bacteria and molds.
• Use a saltwater gargle. A saltwater gargle of 1/4 to 1/2 teaspoon (1250 to 2500 milligrams) of table salt in 4 to 8 fluid ounces (120 to 240 milliliters) of warm water can help soothe a sore throat. Gargle the solution and then spit it out. Most children younger than 6 years aren't able to gargle properly.
• Try other throat soothers. Use ice chips, lozenges or hard candy to soothe a sore throat. Use caution when giving lozenges or hard candy to children because they can choke on them. Don't give lozenges or hard candy to children younger than 6 years.
• Try saline nasal drops or sprays. Saline nasal drops or sprays can keep nasal passages moist and loosen mucus.
• Use a suction bulb for younger children. In infants and younger children, apply saline nasal drops, wait for a short period and then use a suction bulb to draw mucus out of each nostril. Insert the bulb syringe about 1/4 to 1/2 inch (6 to 12 millimeters).

The science isn't clear on alternative cold remedies such as vitamin C, echinacea and zinc. Because studies of alternative cold remedies in children are limited, these remedies are most often not recommended for use in children. Here's an update on some popular choices:

Vitamin C

Taking vitamin C is unlikely to prevent the common cold. Some studies have found that taking vitamin C before cold symptoms start may shorten the length of time you have symptoms.

Echinacea

Study results for echinacea are mixed. Some studies show no benefit. Others show that echinacea may lessen symptoms and shorten the recovery time when taken in the early stages of a cold. Different types of echinacea used in different studies may be a reason for mixed results.

Echinacea seems to work best if you take it when you notice cold symptoms and continue it for 7 to 10 days. It appears to be safe for healthy adults, but it can interact with many drugs. Check with your doctor before taking echinacea or any other supplement.

Zinc

Several studies show that zinc supplements may reduce the length of a cold. But research has turned up mixed results about zinc and colds.

Some studies show that zinc lozenges or syrup reduce the length of a cold by about one day, especially when taken within 24 to 48 hours of the first signs and symptoms of a cold.

Zinc also has potentially harmful side effects. Intranasal zinc might cause permanent damage to the sense of smell. The U.S. Food and Drug Administration (FDA) issued a warning against using zinc-containing nasal cold remedies because they are associated with a long-lasting or permanent loss of smell.

Talk to your doctor before considering the use of zinc to prevent or reduce the length of colds.

If you or your child has cold symptoms that don't go away or get worse, make an appointment with your health care provider. Here's some information to help you get ready for your appointment.

What you can do

Make a list of:

• Your or your child's symptoms and when they began.
• Key personal information, including major stresses, other health conditions and exposure to people who've been ill.
• Medicines, vitamins or supplements you or your child takes.
• Questions to ask your health care provider.

For a common cold, questions to ask may include:

• What's likely causing these symptoms?
• Are there other possible causes?
• Are tests needed?
• What treatment approach do you recommend?
• What treatments should be avoided?
• How soon do you expect symptoms to improve?
• Is my child or am I contagious? When is it safe to return to school or work?
• What self-care steps might help?
• My child or I have other health conditions. How can we manage them together?

Don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Your health care provider is likely to ask you questions, such as:

• How long have you had symptoms?
• Have symptoms been continuous?
• On a scale of 1 to 10, how would you rate the seriousness of the symptoms?
• Did symptoms improve and then worsen?
• What, if anything, seems to improve the symptoms?
• What, if anything, worsens symptoms?

Your care provider will ask additional questions based on your answers, symptoms and needs. Preparing for questions will help you make the most of your time with the provider.