Amoxicillin (Amoxil) is typically well-tolerated, but nausea, vomiting, and diarrhea are some of its most common side effects. In rare cases, more serious amoxicillin side effects are also possible. Common side effects include diarrhea, rash, nausea, or vomiting. Serious side effects are rare but may include severe diarrhea, allergic reactions, or skin reactions. Side effects of amoxicillin are typically mild and include gastrointestinal issues like upset stomach and diarrhea, as well as headache, rash, abnormal taste, and vaginal yeast infections. However, amoxicillin can cause side effects, allergic reactions, and serious problems if the dose is wrong, the drug is not needed, or human products are used without a veterinarian’s guidance. The most common side effects of amoxicillin are skin rash, nausea, vomiting, and diarrhea. It may also cause allergic reactions or serious side effects, but those are less common. Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Amoxil is a prescription medicine used to treat the symptoms of many different types of bacterial infections. Learn about different usages, dosages, side effects, drug interactions, warnings, and more. Amoxicillin is a type of penicillin antibiotic that treats bacterial infections. Common brand names include Amoxil®, Moxilin®, Sumox and Trimox. Learn about the side effects of amoxicillin, from common to rare, for consumers and healthcare professionals. Questions about amoxicillin side effects? This article covers general information. Ask Doctronic about your symptoms, medications, side effects, or treatment options.