Antiinfective agents are those agents used to treat pathological intruders into the human body, such as bacteria, viruses, protozoa and such. If these agents are chemical, this is referred to as chemotherapy, a term that is also used in the epic war against cancer. In order for a drug to be truly effective, it should ideally have selective toxicity, and not kill the host as much as the disease.
Some of the most popular drugs with the kids these days are the antibiotics, which are used to combat and kill bacteria. One problem with these drugs, however, is that bacterial resistance may develop to these agents.