Amoxicillin is a form of penicillin, which is an antibiotic that treats numerous bacterial infections such as strep throat. Tell your doctor about all the other medications you are taking and any allergies so he can make sure amoxicillin is right for you. Amoxicillin can be used as a cure for chlamydia, Although typically it isnt used much anymore because people have built up a resistance to s. view more. Canker sores can be extremely painful. The round sores, also known as aphthous ulcers, are lesions that develop inside the mouth. They usually have a yellow or white. How to Treat Canker Sores. No, cold sores are caused by a virus (Herpes Simplex) and since amoxicillin is an antibiotic, it would have no affect on the virus. Canker sores are small mouth ulcers that may cause severe pain and discomfort. They are usually benign and do not lead to or become oral cancers. Amoxicillin side effects. Amoxicillin is a penicillin antibiotic used to treat bacterial infections, including bronchitis, pneumonia, and infections of the ear, nose, throat, skin, and urinary tract. So, how to treat canker sores? In patients with a few or minor canker sores , usually no treatment is needed apart from simple canker sore relief like a canker sore mouthwash. This simple canker sore remedies can be made at home just by mixing sodium bicarbonate (baking soda) in warm water to keep the mouth clean. Amoxil (amoxicillin) is a penicillin-type antibiotic used to treat infections caused by bacteria that are B-lactamase negative (B-lactamase positive bacteria are usually resistant to Amoxil); these infections usually occur in the skin, lungs, urinary tract and eye, ears, nose, and throat. Canker sores appear in the mouth and can be painful. Learn from the experts at WebMD about causes, symptoms, and treatment. Learn from the experts at WebMD about causes, symptoms, and treatment. Amoxicillin is a penicillin antibiotic treatment for a wide range of bacterial infections such as bronchitis, pneumonia and tonsillitis, as well as infections of the ear, nose, throat and urinary tract. Yes: Yes, you can get canker sores on the gums, cheeks, the soft palate (the back upper portion of your mouth) and very commonly on the tongue.