The following information was written to the best of my ability to be as accurate as possible, yet I am not a doctor, nor a trained researcher. Please let me know of any mistakes below.
What is Ulcerative Colitis?
Ulcerative colitis is an inflammatory bowel disease that usually only affects the mucosal and first tissue layer of the colon. Ulcers in the colon cause pain and bleeding, leading to symptoms of bloody diarrhea with mucus.
The condition can range from mild to severe and exact symptoms can vary from person to person.
Theories of Causation
Currently, there are several theories as to what causes it, including genetic pre-disposition, environmental influences and an autoimmune response.
In the medical community, many diseases are believed to be of an autoimmune type. In an autoimmune condition, the immune system behaves incorrectly and attacks the body. Ulcerative colitis is thought of as being an autoimmune disease, but this not widely accepted by all. 
If ulcerative colitis is not an autoimmune disease, then what is it? I believe it may be due to a bacterial infection, unknown or unproven at this point.
From the Crohn’s and Colitis Foundation of America, “Many scientists now believe that the interaction of an outside agent (such as a virus or bacterium) with the body’s immune system may trigger the disease, or that such an agent may cause damage to the intestinal wall, initiating or accelerating the disease process.” 
Another inflammatory bowel disease very similar to ulcerative colitis is Crohn’s disease. It is also called an autoimmune disease, but because I have this disease and am very familiar with it I have a little more authority to call into question that label.
I do not believe the immune system in Crohn’s patients incorrectly attacks itself for no reason. There is an agent that triggers the immune system to produce inflammation. Inflammation and diarrhea are the body’s attempts to clear the body of infections.
I believe that agent is a bacterial infection known as Mycobacterium avium subspecies paratuberculosis (MAP). My research and personal history strongly suggests my immune system was devastated by acne antibiotics and another acne medication called Accutane. Accutane has been implicated in the cause of both Crohn’s disease and ulcerative colitis.  This devastation of my immune system left me vulnerable to bacterial infections and thus I picked up MAP while traveling.
Food and Bacteria
Food directly affects the bacterial ecology in our guts.   There are several diets in use by those with inflammatory bowel diseases that in theory directly affect the bacterial population in our guts. What’s interesting to note is that both Crohn’s disease and ulcerative colitis patients who use these diets, the Specific Carbohydrate Diet, and Gut and Psychology Syndrome diet, can see incredible and dramatic life changing improvements in their conditions, myself included.
If both of these diets in theory work by changing the bacterial ecology inside our intestines and both Crohn’s and colitis patients achieve long lasting remission through their use, doesn’t it then point to that perhaps ulcerative colitis comes from an infection of bacterial origin?
Antibiotics and Probiotics
Many people I talk to explain to me their disease, either Crohn’s or colitis started after travel and or after use of antibiotics. Antibiotics are used to kill bacteria in our intestines. Too much use and they wipe out both the good and bad populations of bacteria. With an empty gut, good and bad race to setup shop and sometimes the bad like clostridium difficile (c. diff) can win the race.
Without a healthy eco-system of bacteria, we are dead. We cannot convert food into vitamins or absorb nutrients. Good bacteria also fight bad bacterial infections. We know very little about everything bacteria do for the human body, but there are trillions of species of them. Yes, that is not a typo, trillions! In fact, bacteria make up 70% – 80% of our immune system.
You could think of people as not being human at all, but instead a super-organism of interconnected and symbiotic life forms.
Probiotics have proven to be very effective in the treatment of digestive conditions from Irritable Bowel Syndrome (IBS) to Crohn’s disease and ulcerative colitis. In fact, the probiotic VSL #3 has studies proving it’s efficacy for ulcerative colitis patients. 
So many people see dramatic improvement after finding a probiotic supplement that works for them and again, I’m one of them.
Rather than Crohn’s disease and ulcerative colitis being autoimmune diseases, I believe they are diseases of dysbiosis, which means an imbalance of gut bacteria ecology. There are lots of probiotic manufacturer’s out there, but when you buy a probiotic you are only receiving a tiny fraction of all the beneficial bacteria one needs.
Remember, there are trillions of bacterial species and many have yet to be discovered. If one can’t purchase bacterial ecologies and supplement their intestines with them, what else can they do?
In Search of Perfect Poop
The simple truth is that healthy people have a healthy bacterial ecology and unhealthy people do not. If one wants to restore their unhealthy bacterial ecology to a healthy state, they need to transplant a healthy bacterial ecology into their bodies. That ecology while found in the intestines is also found in our poop. I am not kidding.
Fortunately for us, there exists a treatment called Human Probiotic Infusion (aka Fecal Bacterialtherapy, Fecal Transplants).  It is a rare and unknown treatment, primarily for ulcerative colitis and colostridium difficile (c. diff) infected patients.
Since this article is long, I have decided to break it up into two parts. In part 2 I talk about Fecal Transplants in more detail and reveal some good news I have to share related to the documentary.
If you would like more info about this treatment, see the Sources links below 7, 8, 9, 10 and 11.
 Google search for Accutane lawsuits
 Personal anecdotes on HealingWell.com