Prescription. Top view of a doctor's hand signing a prescription for a course of the antibiotic drug amoxycillin to be taken in 250 milligram capsules. Next to his hand is a stethoscope, a device used for listening to sounds in the body made by the heart and lungs. Amoxycillin is a broad-acting anti-bacterial drug similar to penicillin. It is mostly used to treat bronchitis, cystitis, gonor- rhoea, and ear and skin infections.