SIDE EFFECTS: Stomach upset, headache, nausea, vomiting, or diarrhea may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if any of these highly unlikely but very serious side effects occur: stomach/abdominal pain, persistent nausea/vomiting, yellowing eyes or skin, dark urine, new signs of infection (e.g., persistent sore throat or fever), easy bruising/bleeding, signs of kidney problems (such as change in the amount of urine), mental/mood changes (such as confusion). This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a resistant bacteria. This condition may occur while receiving therapy or even weeks to months after treatment has stopped. Do not use anti-diarrhea or opioid medications if you have the following symptoms because such products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, or blood/mucus in your stool. Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection (oral or vaginal fungal infection). Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge or other new symptoms. A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), unusual joint pain, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking cefaclor, tell your doctor or pharmacist if you are allergic to it; or to penicillins or other cephalosporins; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: severe kidney disease, intestinal disease (colitis). Cefaclor may cause live bacterial vaccines (such as typhoid vaccine) to not work as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to. Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, elderly people may be more sensitive to this drug. This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor. This medication passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with them first. See also How to Use. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: warfarin. Although most antibiotics are unlikely to affect hormonal birth control such as pills, patch, or ring, a few antibiotics (such as rifampin, rifabutin) can decrease their effectiveness. This could result in pregnancy. If you use hormonal birth control, ask your doctor or pharmacist for more details. This medication may cause false positive results with certain diabetic urine testing products (cupric sulfate-type). This drug may also affect the results of certain lab tests. Make sure laboratory personnel and your doctors know you use this drug. This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include severe vomiting, seizures.