In the late 1800s a search for antibiotics began in accordance with the growing acceptance that bacteria and microbes have a causal effect on the human body leading to a variety of ailments. From this point in time onward there has been a pursuit for drugs to deter or kill this disease causing bacteria.  Antibiotics can be seen in use for serious life-threatening illness, such as pneumonia, kidney and heart infections, or after major operations to reduce the chances of infection, but also for non-serious ailments such as sore throat or ear infections.  With the wide range that such antibiotics can be utilized for there must be wonder of what exactly the effects, to the human body especially the microbiota in the intestinal tract, are due to the over prescription of antibiotics.  

The human body, within the intestines alone, contains approximately 10 trillion microbes.  These microbes within the intestines take on the role of an organ in the way of their metabolic activity.  Intestinal microbes are there to aid in digestion, nutrition, maintain a healthy immune system, and protect when harmful microbes invade.  When an antibiotic is introduced into the ecosystem of the human body it does not have the capability to segregate the harmful bacteria from the ones that are needed, so there is destruction of all types of bacteria.  The destruction of the microbiota in the gut leads to a less diversified spectrum, which can lead to such things as the inflammatory bowel disease (IBS).

According to the studies of Vincent B. Young, a researcher at the University of Michigan,  has taken the question of what the effects of antibiotic on the human gut into consideration has discovered a few interesting facts, with the use of mice.  A sequence analysis was done on the bacterial communities within the gut with the use if the 16S rRNA encoding gene libraries.  With the use of baby mice, which have a non-diverse realm of bacteria, two antibiotics were tested.  These two antibiotics, cefoperazone and a combination of three antibiotics (amoxicillin, bismuth and metronidazole), both causes changes within the microbiota community.  After the use of the cefoperazone there was no recovery to the normal diversity while the other led to an almost fully recovered diversity.  The research from these studies will further go into the investigation of how such change can cause many of the intestinal problems that seem to be common today.