Most side effects are mild and self‑limited. Gastrointestinal symptoms (diarrhea, nausea) and rash are most common in children. Serious reactions like anaphylaxis or C. difficile–associated diarrhea (CDAD) are rare but require urgent care.
Cefaclor’s pediatric safety profile is similar to other oral cephalosporins. GI upset often improves if given with food. Allergic reactions can occur in those with beta‑lactam hypersensitivity.
3 documented effects
Not specified
Maintain hydration; consider giving with food; avoid antidiarrheals unless instructed
Call if severe, persistent >3 days, bloody, or accompanied by fever
Not specified
Give with food; small sips of fluids after dosing
Call if persistent vomiting or signs of dehydration
Not specified
Stop drug; prompt clinical evaluation
Watch for watery diarrhea, abdominal pain, fever; seek care immediately
2 documented effects
Not specified
Call clinician for evaluation; continue if mild and child otherwise well unless advised
Stop and seek urgent care for hives, facial swelling, mucosal involvement, or blistering
Not specified
Stop medication and seek urgent care
Monitor for symptom escalation or new adverse effects.
1 documented effect
Not specified
Stop immediately; emergency care
Monitor for symptom escalation or new adverse effects.
1 documented effect
Not specified
Supportive care
Monitor for symptom escalation or new adverse effects.
For babies taking cefaclor, mild tummy upset can happen and usually goes away on its own.
If your toddler is on cefaclor, they might have a little stomach upset or loose stools. This is usually mild.
Cefaclor can sometimes cause mild diarrhea or stomach upset. Encourage fluids and let us know if it’s persistent.
Some teens notice mild GI upset with cefaclor. Taking with food can help unless told otherwise.
A: Mild diarrhea is common and often improves within a couple of days.
When to validate: Call if diarrhea is severe, bloody, or signs of dehydration appear.
A: A mild rash can occur. Seek urgent care for hives or breathing trouble.
When to validate: Stop medication and call urgently for hives, swelling, or breathing problems.
Clinical assessment framework for cefaclor adverse effects.
Parent and clinician concerns about Cefaclor