Clindamycin: what it treats, how to take it, side effects
Last updated September 3, 2026.
Clindamycin is a lincomycin antibiotic - it slows and stops the growth of bacteria. It treats certain bacterial infections, and it carries the antibiotic world's most famous warning: the diarrhea that can start during treatment or weeks after it ends.
What does it treat?
Certain types of bacterial infections. Like all antibiotics, it does nothing for colds, flu, or other viral infections - and using it when it is not needed raises your risk of a resistant infection later.
How do you take it?
Three to four times a day, at the same times every day, for as long as the prescription runs. Two mechanical rules matter: swallow each capsule with a full glass of water, and do not lie down for at least 30 minutes after taking it - the capsule can irritate your throat on the way down. If you use the liquid, store it at room temperature, never the refrigerator (it thickens), and discard what is left after 2 weeks. Finish the whole prescription even when you feel better by day three - stopping early is how resistant bacteria win. Missed dose: take it when you remember unless the next one is close; never double up.
Side effects to know
- Common: nausea, vomiting, an unpleasant or metallic taste, joint pain, and vaginal discharge, burning, itching, or swelling.
- Serious - call your doctor immediately or get emergency care: rash, hives, itching, or peeling or blistering skin; hoarseness, trouble breathing or swallowing, or swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs; yellowing of the skin or eyes; decreased urination; new or worsening heartburn; and pain or difficulty when swallowing.
Who should not take it?
The warning to know: clindamycin can let dangerous bacteria overgrow in the large intestine - anything from mild diarrhea to a life-threatening colon inflammation. Watery or bloody stools, diarrhea, stomach cramps, or fever during treatment or in the several months after it ends mean calling your doctor. Flag any past colitis or other stomach and intestinal conditions, plus asthma, allergies, eczema, and kidney or liver disease. If you become pregnant, call your doctor.
When is it an emergency?
Trouble breathing or swallowing, or swelling of the face, tongue, or throat, is a 911 call. Bloody diarrhea with cramps and fever means same-day care, during the course or months after it. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Why do I have to finish all the clindamycin if I feel better?
Feeling better means the bacteria are losing, not gone. MedlinePlus says stopping early or skipping doses can leave the infection incompletely treated - and the surviving bacteria can become resistant to antibiotics. The last pills in the bottle are doing the actual curing. The one exception: the serious-side-effect list, especially watery or bloody diarrhea, means calling your doctor before the next dose.
What is the diarrhea warning about clindamycin?
The drug can clear out protective gut bacteria and let dangerous ones overgrow in the colon - anything from mild diarrhea to a life-threatening colon inflammation. MedlinePlus says it can happen during treatment or up to several months after. Watery or bloody stools, diarrhea, stomach cramps, or fever in that window means calling your doctor, and mentioning the clindamycin by name.
Why can't I lie down after taking clindamycin?
The capsule can lodge and irritate. MedlinePlus says take it with a full glass of water and stay sitting or standing upright for at least 30 minutes - clindamycin capsules are known for burning the esophagus on the way down. Pain or trouble swallowing on this drug is a call-your-doctor symptom.
Why shouldn't clindamycin liquid go in the fridge?
It thickens. MedlinePlus says do not refrigerate clindamycin liquid because it may become hard to pour - room temperature storage instead, tightly closed. And it does not keep: discard whatever is left after 2 weeks.
Can I drink alcohol while taking clindamycin?
Neither the label nor MedlinePlus gives clindamycin-specific alcohol language. Alcohol irritates the same gut the drug is working on and dehydrates you during an infection. Light or none for the course is the practical call - ask your doctor for your situation.
Will clindamycin work for my cold?
No. MedlinePlus states it directly: antibiotics such as clindamycin will not work for colds, flu, or other viral infections, and using antibiotics when they are not needed increases your risk of getting a resistant infection later. It is prescribed for specific bacterial infections - taking it for a virus only costs you.