Greg Developed and Ear infection. His doctor gave him an antibiotic. The antibiotic killed all the bacteria in his body. What other effect could the antibiotic have

Antibiotics can have side effects.
When children take antibiotics at the first sign of an ear infection, they are more likely to have vomiting, diarrhea, and allergic reactions because of the medicine. Also, antibiotics can kill “friendly” germs in the body and cause other problems like diarrhea.

Over-use of antibiotics is a problem.
Antibiotics can help drug-resistant bacteria grow. These bacteria are harder to kill. They can cause illnesses that are harder to cure and more costly to treat. This increases the risk of complications and side effects. The resistant bacteria can also infect other people.

Hope this helps