

Antibiotics target specific features of bacterial cells that are different from human cells. This selectivity helps them fight infections without harming you. Bactericidal antibiotics kill bacteria directly. Bacteriostatic antibiotics inhibit bacterial growth and prevent bacteria from multiplying, stopping the infection from progressing and clearing the way for the immune system to fight back.
Different categories of antibiotics use different mechanisms to fight disease:
Chances are, you’ve mostly taken antibiotics orally, in pill or liquid form. For external infections, such as those affecting the skin, ears, or eyes, topical antibiotics, which are applied to the affected area, may be prescribed. Some antibiotics used for sinus infections are delivered via nasal sprays. Others may be given as an injection or intravenously, through an IV. These are typically used for more serious infections, when it’s essential to get medication in your system ASAP.
According to the health and science platform Science Direct, antibiotics have extended the average human lifespan by 23 years over the course of the last century. The benefits of these drugs are clear. They can:
Like most drugs, antibiotics can have side effects. The most common ones include nausea and vomiting, dizziness, rashes, yeast infections, and diarrhea. Antibiotics, particularly the less targeted broad-spectrum drugs such as amoxicillin, erythromycin, or doxycycline, can kill beneficial bacteria, like the intestinal gut flora that help with digestion, or the bacteria that keep Candida from multiplying excessively and causing yeast infections. While you are taking antibiotics, consuming fermented foods that contain probiotics, such as sauerkraut, yogurt, kimchi, or tempeh, can help replenish some of those beneficial bacteria.
Serious side effects from taking antibiotics are less common. Allergic reactions can range from a skin rash to blistering of the skin, swelling of your face, lips, tongue or throat, breathing problems, dizziness, rapid heartbeat, and anaphylaxis.
Do tell your healthcare provider about any and all medications you are taking. Some may interact with the antibiotic you are on. Certain antibiotics interact with blood thinners, antacids, NSAIDs, beta blockers, anti-depressants, and other medications. Calcium or iron supplements can interfere with the absorption of certain antibiotics.
Don’t drink alcohol while you are on your antibiotic without checking with your doctor first. Some antibiotics will cause nausea and vomiting when combined with alcohol.
Do talk to your pharmacist about your prescription and potential side effects. Make sure to read the information you receive with your medication.
Do take your medication as prescribed. Stopping the medication as soon as your symptoms disappear is a mistake. The infection could come roaring back, and the bacteria could develop a resistance to the antibiotic.
Don’t save or share your antibiotics, or take medication prescribed for someone else. The drugs may be past their expiration date, or you may not have enough to cure an infection. Moreover, many antibiotics are developed to fight specific infections. Just because one antibiotic worked against strep throat doesn’t mean it can treat a UTI.
Don’t take antibiotics unless prescribed by a doctor. Taking antibiotics too often or unnecessarily contributes to the growth of antibiotic-resistant organisms.
Don’t take antibiotics for a viral infection. Antibiotics are ineffective against viruses.
Do tell your doctor if you think you might be pregnant. Certain antibiotics, such as tetracycline, can cause birth defects.
Do call your doctor if you experience any of the side effects described in this article. If you think you may be going into anaphylactic shock, call 911.
This article first appeared in the August 2025 edition of the HealthPerks newsletter.
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