Antibiotics are effective medications to treat bacterial infections. However, most upper respiratory infections are actually caused by viruses. Treatment of viruses with antibiotics is ineffective and may put you at risk for significant side effects such as diarrhea, upset stomach, yeast infections and allergic reactions. In addition, unnecessary usage of antibiotics can worsen a national problem of antimicrobial resistance which may put you and others at risk for more severe infections in the future. Your doctor will consider your symptoms and recommend the most appropriate and safest treatment.