Whats the most severe thing you have found in somebody’s body? And how come that drugs cant always work, is it because

Question: Whats the most severe thing you have found in somebody's body? And how come that drugs cant always work, is it because of the bacteria growing?
- Keywords:
- Royal Society of Chemistry: Find out more about:
  
  bacteria
  
  drug
Asked by Ellen to Alex, Anaïs, Peter, Sarwat, Shreesha on 19 Mar 2015.
- Peter Maskell answered on 19 Mar 2015:
  
  mmm….probably a drug that killed them. some people may not have the target the drug is looking for.

Question: Whats the most severe thing you have found in somebody's body? And how come that drugs cant always work, is it because of the bacteria growing?