What Are the Most Common Side Effects of onlinerxantibiotics.com Antibiotics? The majority of antibiotics have quite similar side effects. The major part of these effects is related to gastrointestinal problems such as the following: Nausea and vomiting; Diarrhea; Stomach cramps. In certain cases, the side effects provoked by antibiotics can be mitigated if you take the drug together with a meal. However, certain antibiotics should always be taken without food. If you want to be sure that you use your drug correctly, ask the pharmacist or doctor for advice so that you know the best way to use your antibiotic. Digestive problems usually disappear after you stop the treatment process. If they don’t go away, it is necessary to call your doctor.