Skip to main content

How do antibiotics work to kill bacteria?

Medically reviewed by Drugs.com. Last updated on April 1, 2025.

Official Answer by Drugs.com

Antibiotics work by interfering with the bacterial cell wall to prevent growth and replication of the bacteria. Human cells do not have cell walls, but many types of bacteria do, and so antibiotics can target bacteria without harming human cells.

Antibiotics are either bactericidal (they kill the bacteria) or bacteriostatic (they keep the bacteria from reproducing and growing).

Antibiotics have no action on viruses that are the cause of the common cold, the flu, and many coughs, so they are not effective against these types of illnesses.

Read next

Should you take probiotics with antibiotics?

There is controversy about whether you should routinely take probiotics with antibiotics and the question cannot be answered with a straight yes or no. Evidence for taking probiotics with antibiotics includes a Cochrane review which reported that children who were given a course of probiotics after antibiotics had less diarrhea. Evidence against taking probiotics with antibiotics includes a 2019 Italian study that reported that the gut microbiome of people given probiotics after antibiotics took six months to return to its normal state compared to only three weeks for those not given any probiotics. More studies are needed before a definite statement can be made. Continue reading

Can you drink alcohol with amoxicillin?

Yes, you can drink alcohol while taking the antibiotic amoxicillin. The alcohol will not stop amoxicillin from working. However, many health professionals will recommend you avoid alcohol to give your body the best chance possible to fight the infection. Moderation is key. Continue reading

Doxycycline for STDs: Effectiveness, Dosage and Side Effects

Doxycycline is a broad-spectrum tetracycline antibiotic that may be taken within 72 hours of unprotected sex to help prevent common STDs, such as syphilis, chlamydia, and gonorrhea. This is known as the STD morning-after-pill or Doxy PEP. Continue reading

See also:

Related medical questions

Related support groups