While you may think of antibiotics as a cure-all, they aren’t the answer for every illness. We asked experts to weigh in on your top questions about these medications.

Vaccines with Pink Medicine in Circle
Credit: Travis Rathbone

If your child has suffered from a bacterial infection such as pneumonia or strep throat, you've probably experienced the benefits of antibiotics firsthand. Some antibiotics, like penicillin, work by killing bacteria directly—they're dubbed bactericidal. "This type of antibiotic prevents bacteria from forming their protective wall or making the components they need to live," says Stacey L. Schultz-Cherry, Ph.D., an infectious-disease expert at St. Jude Children's Research Hospital, in Memphis. 

Other antibiotics, like erythromycin, work more indirectly by causing the bacteria to stop multiplying without outright killing them.These are called bacteriostatic antibiotics (often prescribed for ear infections). "They can work with the immune system to fight the infection,"explains Dr. Schultz-Cherry.

Antibiotics work quickly in children; symptoms usually improve dramatically within 24 to 48 hours of starting the medicine. Many times, kids feel completely well shortly after beginning the antibiotic course (although your child should finish the entire course as prescribed). 

It's important to realize, though, that not all that glitters is gold. Side effects and resistant bacteria have created a double-edged sword with these medicines. Here are the most up-to-date facts about antibiotics to answer some common questions.

What Can Antibiotics Cure?

Kids tend to pick up run-of-the-mill illnesses, and these prescribed meds can be the magic pill you're looking for to help them feel better fast, says Lisa Stern, M.D., a pediatrician at Tenth Street Pediatrics, in Santa Monica, California. But there's a big catch. "Antibiotics fight only infections caused by bacteria—they have no potency against viruses," Dr. Stern explains. Bacteria are pretty sneaky, because they're living, replicating, and dividing in your body all the time, says Dr. Schultz-Cherry.

So how do doctors know if your kid has a viral or a bacterial infection? The truth is, sometimes it's tough to differentiate between the two. "The ever-so-slight variation of mucus color could determine what your kid is sick with. Viral pneumonia, for example, may come with clear mucus and a mild fever, whereas a bacterial infection may bring yellow or green mucus and a high fever," Dr. Schultz-Cherry says. However, a viral infection can also develop into a secondary bacterial infection while your body is trying to recover from a virus like a cold or even influenza. "The most common types of secondary bacterial infections in children include ear infections, sinus infections, and pneumonia," explains Kimberly Montez, M.D., M.P.H., a Parents advisor and assistant professor of pediatrics at Wake Forest School of Medicine, in Winston- Salem, North Carolina. 

The good news is that kids are great at letting their bodies do the talking, Dr. Montez says. "Children with bacterial infections may not want to eat and will appear tired or will sleep more than usual." Or if they're not peeing as often, they may be dehydrated, another sign that something is amiss and that you should take them to the pediatrician's office. 

Certain tests help your doctor figure out whether your kid's infection is bacterial or viral, says Mason Gomberg, M.D., a pediatrician at White Plains Hospital Physician Associates, in New York. "They might include blood work, cultures taken from your child's throat, urine, or blood, or a chest X-ray." These results, along with an exam and a health history, will help determine if your child has a bacterial infection.

How Do Doctors Prescribe Antibiotics?

Your provider will know which antibiotic will be effective for the infection your child has, but you can always bring up any concerns about the antibiotic choice dosage, timing, or effects, says Yvonne Maldonado, M.D., Parents advisor and professor of pediatrics, global health, and infectious disease at Stanford University School of Medicine. 

Different antibiotics are designed to fight different types of bacteria; just because the pink stuff worked for your son's ear infection doesn't mean that it's the best choice for your daughter's pneumonia. Some antibiotics are what we call broad-spectrum, meaning they kill a wide range of bacteria. "When we don't know the exact bacterium causing the infection, we prescribe one of these," says Dr. Gomberg. Narrow-spectrum antibiotics target only a few strains of bacteria; these treat conditions such as uncomplicated skin infections, ordinary ear infections, and most strep throat infections. 

Narrow-spectrum antibiotics are commonly prescribed over broad-spectrum ones because they have fewer side effects—and because doctors don't want to allow resistant strains of bacteria to grow. Using a broad-spectrum antibiotic to treat a simple ear infection is like using a bazooka to kill a fly. It will work, but the collateral damage may be worse than the bug you were targeting.

Antibiotic Resistance: Can These Medicines Do More Harm Than Good?

According to Dr. Gomberg, "The unfortunate thing is, a broad-spectrum antibiotic, such as doxycycline, will kill the good bacteria along with the bad. This can lead to an increase in bacterial antibiotic resistance and is one reason why antibiotics should be used only when absolutely necessary." If antibiotics change the intestinal flora and get rid of good bacteria in the gut, Dr. Gomberg explains, an invasive gastrointestinal bacterium called Clostridium difficile (or C. diff) can take over in the colon and cause nausea, belly pain, fever, severe diarrhea, and, in rare cases, life-threatening inflammation of the colon.

So what exactly is antibiotic resistance? Through repeated use and misuse of antibiotics in the general population, bacteria can change, mutate, and become resistant to a specific medication. "It's scary because it means that someday an antibiotic may stop working," says Grace Averitt, D.O., a pediatrician at Austin Regional Clinic. "We can help prevent antibiotic resistance by taking antibiotics exactly as prescribed, not taking other people's, and taking them only for bacterial illnesses."

If your child is being prescribed antibiotics frequently, Dr. Averitt strongly suggests that you ask why they're needed and discuss this concern with your pediatrician, who can help you find other fixes for the problem. For example, if your child has frequent strep-throat infections, "they may need to be referred to a specialist to evaluate possibly removing their tonsils," she says.

It's also vital for your child to take all antibiotics in the course. Skipping doses or ending early might leave harmful bacteria in their body, possibly causing the infection to come back again. Also, the strongest bugs are likely to stick around longest, and they're more likely to be resistant, says Anastasia Levitin, Ph.D., of the Keck Graduate Institute, in Claremont, California..

Do Antibiotics Have Side Effects?

Antibiotics not only kill or alter the bad bacteria, but they can also disrupt the gut's normal flora, or good bacteria, that help keep our digestive tract healthy, says Amna Husain, M.D., a pediatrician and founder of Pure Direct Pediatrics, in Marlboro, New Jersey. This unfortunate side effect usually shows up as nausea or diarrhea. "Taking a probiotic while on antibiotics will help restore your child's good gut bacteria," says Dr. Husain. When your child is prescribed an antibiotic, ask their pediatrician about which probiotic might be most effective. Other antibiotic side effects include diaper rash, discoloration of stool or urine, and sun-sensitivity-rash.

What's more, between 1 and 10 percent of the American population has penicillin allergies (the most common antibiotic allergies), but less than 0.01 percent of people actually experience life-threatening allergic anaphylaxis to penicillin. The most common indication of an antibiotic allergy is a rash. However, rashes that develop while you're taking an antibiotic are often part of the illness itself and not an indication of an allergic reaction to the medication. Always contact your pediatrician if your child develops a rash while taking an antibiotic; they'll help you determine whether your child should avoid that antibiotic in the future.

How Can I Make It Easier for My Child to Take Antibiotics?

Sometimes the best antibiotic for your child is the one that tastes the worst. You can blame the chemical structures of certain medications for that terrible taste, says Megan N. Freeland, Pharm.D., a pharmacist in Atlanta. If you ask, some pharmacists may be able to add flavoring to your child's medication to make it more appealing. "If it's a liquid form, try using a syringe to squirt the medication into your child's lower cheek in short bursts instead of directly onto the tongue all at once," Dr. Freeland says. You might also camouflage the bad taste in a spoonful of something like pudding or applesauce (but don't put antibiotics in a baby's bottle, because it's difficult to guarantee they'll drink the entire dose at one time).

If your child absolutely refuses to open up and take the medicine or cannot keep down a liquid antibiotic, Dr. Freeland suggests asking your doctor if there's a better-tasting alternative, a chewable, or an injection option (if your kid tolerates needles, that is). "My 3-year-old recently refused to take his amoxicillin for an ear infection, even with the bubble-gum flavoring," says Parents senior features editor Katie Arnold-Ratliff. "Our pediatrician recommended getting a shot of antibiotics injected into each of his legs instead. While my son didn't enjoy the shots much, either, within two days his earache was gone."

Physicians also often recommend that kids take certain antibiotics with a meal. One reason is that eating while downing an antibiotic can help mask the not-so-great taste. But the bacteria can also mess with the normal balance of your kid's digestive tract, so it's often easier to tolerate medications on a full stomach. "Even if your kid is feeling under the weather or says they're not hungry, encourage them to take the meds with a banana or a cracker," suggests Suzanne Soliman, Pharm.D., founder and president of the Pharmacist Moms Group and Florajen pharmacist consultant.

Common Antibiotics for Kids

These antibiotics are often used for kids. Your doctor can determine the proper medicine and dosage based on the specific illness.

Amoxicillin: Prescribed to treat ear infections, strep throat, sinusitis, and pneumonia

Azithromycin: Used for pneumonia and pertussis, and for kids with a penicillin-related allergy

Cephalexin: Typically given to tackle skin or urinary tract infections

Clindamycin: An oral antibiotic for skin infections, and for infections in kids with a penicillin-related allergy

Trimethoprim-sulfamethoxazole: An alternate med for skin or urinary tract infections