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., Amoxicillin can cause various side effects. These include nausea, headache, and diarrhea. Although most amoxicillin side effects are not serious, some people have reported life, Common side effects of amoxicillin are generally temporary and include rash, diarrhea, headache, nausea, vomiting, stomach pain, tongue discoloration, yeast infection, elevated liver enzymes, and high white blood cell counts., Common side effects include diarrhea, rash, nausea, or vomiting. Serious side effects are rare but may include severe diarrhea, allergic reactions, or skin reactions., What Are Side Effects of Amoxil (amoxicillin)? Common side effects of Amoxil include: nausea vomiting diarrhea stomach pain vaginal itching or discharge headache rash, and swollen, black, or "hairy" tongue. Other serious side effects of Amoxil include: colitis caused by overgrowth of Clostridium spp in the intestines, fever, burning eyes, sore , What side effects can this medication cause? Amoxicillin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away: nausea vomiting diarrhea temporary discoloration (yellow, brown, or gray color) of your teeth Some side effects can be serious..