Antibiotics: when they work, when they don’t, and how to use them safely
Última actualización: 7/14/2026
Antibiotics are powerful medicines used to treat infections, but they are often misunderstood or used when they are not needed. Taking a few minutes to understand when antibiotics work and how to use them correctly can help protect your health and ensure these medicines remain effective in the future.
Using antibiotics appropriately is one of the most important steps you can take to protect your health and prevent antibiotic resistance.
Understanding when antibiotics are needed, and when they are not, can help you make informed decisions about your care. Here are key facts to know before you take antibiotics.
Key facts about antibiotics
- Antibiotics treat bacterial infections, not viruses
- They do not work for colds, flu, or most sore throats
- Misuse can lead to antibiotic resistance
- Always take antibiotics exactly as prescribed
What are antibiotics and how do they work?
Antibiotics are medicines used to treat infections caused by bacteria. According to the Centers for Disease Control and Prevention (CDC), antibiotics work by killing bacteria or stopping their growth so your body can fight off the infection.
They are an important tool in modern medicine, helping treat infections that could otherwise become serious or life-threatening.
What infections do antibiotics treat?
Antibiotics are used to treat infections caused by bacteria, not viruses. According to the Centers for Disease Control and Prevention (CDC), antibiotics are commonly prescribed for bacterial infections such as strep throat, urinary tract infections, and certain types of pneumonia.
They may also be used for some skin infections, sinus infections, and ear infections when a bacterial cause is confirmed.
Understanding what antibiotics treat can help you have better conversations with your healthcare provider and avoid unnecessary use.
Do antibiotics work on viruses, colds, or the flu?
No. Antibiotics do not work on viruses.
The CDC explains that illnesses such as colds, flu, most sore throats, and bronchitis are caused by viruses, not bacteria. Taking antibiotics for these conditions will not help you recover.
Using antibiotics when they are not needed can also contribute to antibiotic resistance, making future infections harder to treat.
What to do when you have a cold or flu
If you have a cold or flu, there are other ways to manage your symptoms safely.
According to the CDC, the best approach includes rest, staying hydrated, and using over-the-counter medications to relieve symptoms.
You can also:
- get plenty of rest
- beba mucha agua
- use symptom-relief medications and a humidifier
- stay home to prevent spreading illness
- wash your hands often
A pharmacist or healthcare provider can help guide you toward the right treatment.
When should you take antibiotics?
Antibiotics should only be used when prescribed by a healthcare provider for a confirmed bacterial infection.
The CDC recommends taking antibiotics exactly as prescribed and completing the full course of treatment, even if you start to feel better.
If you are prescribed antibiotics:
- take them exactly as directed
- do not skip doses
- do not share them with others
- do not save them for later
Stopping antibiotics too early can allow bacteria to survive and continue to grow.
How long do antibiotics take to work?
The time it takes for antibiotics to work depends on the type of infection and the medication prescribed. According to MedlinePlus, many people begin to feel better within a few days of starting antibiotics, but it is important to complete the full course of treatment.
Different antibiotics also stay in your body for different lengths of time, which is why following your provider’s instructions is important.
If your symptoms do not improve or get worse, contact your healthcare provider.
Antibiotics side effects and risks
Like all medications, antibiotics can cause side effects.
The CDC notes that common side effects from antibiotics may include nausea, diarrhea, rash, and yeast infections.
In some cases, antibiotics can lead to more serious complications. According to the CDC, antibiotic use can increase the risk of Clostridioides difficile (C. diff), an infection that causes severe diarrhea.
If you experience severe or unusual side effects, contact your healthcare provider right away.
What is antibiotic resistance and why does it matter?
Antibiotic resistance occurs when bacteria change and no longer respond to the medicines designed to kill them.
The CDC identifies antibiotic resistance as one of the most urgent public health challenges. According to the CDC, misuse and overuse of antibiotics are key drivers of resistance.
The World Health Organization (WHO) also warns that antibiotic resistance can make infections harder to treat, increase the risk of severe illness, and lead to longer recovery times.
Using antibiotics responsibly helps protect their effectiveness for future patients.
When to talk to your healthcare provider
If you are unsure whether you need antibiotics, talk to your healthcare provider or pharmacist.
They can help determine:
- whether your illness is bacterial or viral
- what treatment is most appropriate
- how to manage symptoms safely
- when antibiotics are necessary
Always reach out if you have questions about medications or side effects.
Lo que Capital Blue Cross puede hacer por usted
Understanding when to use antibiotics is an important part of managing your health, and you don’t have to figure it out alone.
If you’re a Capital Blue Cross member, you have access to tools and support that can help you make informed decisions about your care:
- Connect with your healthcare provider (or find a provider on MyCare Finder) to discuss your symptoms and determine whether antibiotics are appropriate.
- Use virtual care options to get guidance quickly without leaving home.
- Speak with a pharmacist for help understanding your medications and how to take them safely.
If you’re feeling unsure about your symptoms or treatment plan, reaching out early can help you get the right care at the right time.
Explore your member resources or use MyCare Finder to connect with a provider to get started.
Preguntas frecuentes
Do antibiotics treat colds or the flu?
No. According to the CDC, antibiotics do not work on viruses like colds and flu.
What infections do antibiotics treat?
Antibiotics treat bacterial infections such as strep throat, urinary tract infections, and certain types of pneumonia.
How long do antibiotics take to work?
Many people begin to feel better within a few days, but it is important to complete the full course as prescribed to fully clear the infection.
¿Qué es la resistencia a los antibióticos?
Antibiotic resistance occurs when bacteria no longer respond to antibiotics, making infections harder to treat.
Este no es un consejo médico y no pretende sustituir el asesoramiento, diagnóstico o tratamiento médico profesional. Siempre busque el consejo de su médico u otro proveedor de atención médica calificado con cualquier pregunta que pueda tener con respecto a una afección o tratamiento médico. La información que se brinda está dirigida al público en general. Capital Blue Cross y sus empresas afiliadas consideran que este recurso de educación de la salud brinda información útil, pero no asumen ningún tipo de responsabilidad con respecto a su uso.