Antibiotics kill bacteria. Colds are caused by viruses - rhinovirus and friends - so antibiotics do literally nothing for a cold except expose you to side effects and breed the resistant bacteria that are becoming a genuine public crisis.
The mechanics: viruses are not alive the way bacteria are - no cell wall to attack, no machinery to disrupt - so the entire antibiotic toolkit misses. What taking them for a cold actually does: diarrhea, rashes, yeast infections and (rarely) dangerous reactions like C. diff colitis or tendon damage; kills off your protective gut bacteria; and trains the bacteria you carry to survive the drug - resistance that then shows up in the pneumonia or wound infection that happens to you or someone else years later. Antibiotic resistance already kills over a million people a year globally, and unnecessary prescribing is the fuel. When antibiotics ARE right after a cold starts: a bacterial complication - sinus infection past 10 days or 'double-worsening,' strep throat (tested), an ear infection meeting criteria, or pneumonia. The pattern to know: a cold that improves then crashes back with fever is the classic bacterial-superinfection signal. Everything before that point is fluids, rest, honey, and the drugstore symptom playbook. Emergencies skip this list: chest pain, trouble breathing, stroke signs, severe bleeding, or thoughts of self-harm mean call 911, or 988 for a mental health crisis in the US.
What to do
Common questions
But my cold turned into a sinus infection - don't I need antibiotics now?
Probably still no - most sinus infections, even the ones following colds, are also viral and clear in 7 to 10 days. Guidelines reserve antibiotics for sinus symptoms lasting beyond 10 days, severe cases (fever above 102F with days of facial pain), or the 'double-worsening' pattern where you improve then crash. The rest resolve with saline rinses, decongestants and time. The color of your mucus, despite folklore, does not tell viral from bacterial.
If I ask, will a doctor just give me antibiotics anyway?
Some will - patient pressure is a documented driver of the roughly 30% of outpatient antibiotic prescriptions that are unnecessary, and telehealth has its own bad actors advertising antibiotics-on-demand. Treat a clinician who hands them out for a routine cold as a red flag, not a win. The good ones will explain the viral/bacterial line and give you a real symptom plan - that is the better care, not the stingier care.
What actually helps a cold, then?
The honest list: rest (short sleep measurably weakens cold-virus defense), fluids, honey for cough (beats OTC syrups in trials; no honey under age 1), ibuprofen or acetaminophen for aches and sore throat, pseudoephedrine from behind the pharmacy counter for congestion, zinc lozenges within the first 24 hours to shorten it, and saline for everything nasal. Expect 7 to 10 days - a cold has its own schedule.
How will I know when it's become something that needs treatment?
The reliable patterns: symptoms past 10 days without improvement, improvement then a hard crash with fever (secondary bacterial infection), a fever above 102F settling in, ear pain, wheezing or shortness of breath, severe one-sided sinus pain, or a sore throat with fever but no cough (that is strep's pattern - get the rapid test). Any of those is worth a same-day telehealth or clinic visit. Emergencies skip this list: chest pain, trouble breathing, stroke signs, severe bleeding, or thoughts of self-harm mean call 911, or 988 for a mental health crisis in the US.