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Bright red blood during or after bowel movements.
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Blood mixed into the stool.
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Repeated episodes of rectal bleeding.
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Dark, tar-like stool without an obvious explanation.
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Bleeding accompanied by abdominal discomfort or changes in bowel habits.
Heavy bleeding, fainting, severe weakness, dizziness, or black tarry stool accompanied by signs of illness requires urgent medical attention.
The most important principle is simple: visible blood in the stool is a symptom that deserves an explanation. Even when the cause turns out to be relatively minor, getting it checked is safer than making assumptions.
Chapter 3: Unexplained Weight Loss
Losing weight without changing eating habits or increasing physical activity can sometimes be a warning sign of an underlying health problem.
Weight naturally fluctuates. Changes in hydration, appetite, stress, sleep, and daily activity can all influence body weight. However, a noticeable and continuing decrease without a clear explanation deserves medical attention.
Unexplained weight loss may occur when an illness affects appetite, digestion, nutrient absorption, metabolism, or the body's energy requirements.
In some people with colon-related disorders, abdominal discomfort, nausea, changes in bowel habits, or a persistent feeling of fullness can reduce food intake. Inflammatory conditions may also interfere with normal nutrient absorption and contribute to weight loss.
Colorectal cancer is another possible cause. As the disease develops, it may affect appetite, metabolism, and the body's ability to maintain weight. However, weight loss alone is not a reliable way to identify colorectal cancer, and many people with colorectal cancer do not experience this symptom in its early stages.
Other possible causes include:
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Overactive thyroid function.
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Diabetes that is not adequately controlled.
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Chronic infections.
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Gastrointestinal diseases.
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Depression and other mental health conditions.
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Medication side effects.
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Other cancers or chronic medical conditions.
The amount of weight lost and the time period are important. A commonly used clinical threshold for potentially significant unintentional weight loss is approximately 5% or more of body weight over six to twelve months.
For example, someone who weighs 70 kilograms and unintentionally loses around 3.5 kilograms may need an assessment, particularly if the weight continues to decrease.
People should also pay attention to whether weight loss occurs alongside other symptoms.
For instance, unexplained weight loss combined with persistent diarrhea, abdominal pain, rectal bleeding, or unusual fatigue may require more thorough investigation than weight loss occurring alone.
A healthcare professional may review eating habits, medical history, medications, and recent changes in health. Depending on the findings, blood tests, stool tests, imaging, or colonoscopy may be recommended.
Unintentional weight loss should not be treated as a positive health achievement simply because the number on the scale is decreasing.
When weight falls without a clear reason, the priority should be identifying what is causing the change.
Chapter 4: Persistent Abdominal Pain, Bloating, and Discomfort
Abdominal discomfort is extremely common. Almost everyone experiences bloating, gas, cramps, or stomach pain occasionally.
These symptoms may occur after eating too quickly, consuming certain foods, experiencing stress, or developing temporary constipation.
However, persistent or recurring abdominal discomfort can sometimes indicate a problem involving the colon or another part of the digestive system.
The location and nature of the discomfort can vary. Some people experience cramps in the lower abdomen, while others describe pressure, fullness, sharp pain, or a persistent sensation that their stomach feels swollen.
Bloating that repeatedly occurs alongside changes in bowel habits may be associated with irritable bowel syndrome, food intolerances, constipation, or inflammatory conditions.
Irritable bowel syndrome, commonly known as IBS, is a disorder involving interactions between the digestive system and nervous system. It can cause abdominal pain, bloating, constipation, diarrhea, or alternating bowel patterns.
Although IBS can significantly affect quality of life, it does not cause colorectal cancer. However, people should not assume that persistent digestive symptoms are IBS without receiving an appropriate evaluation.
Inflammatory bowel diseases, including Crohn's disease and ulcerative colitis, can also cause abdominal pain and changes in bowel movements.
These conditions involve chronic inflammation of the digestive tract. Symptoms may include diarrhea, rectal bleeding, fatigue, reduced appetite, and unintended weight loss.
In certain cases, diverticular disease can contribute to abdominal pain. Diverticula are small pouches that can develop in the wall of the colon. When these pouches become inflamed or infected, a condition called diverticulitis may develop.
Diverticulitis often causes pain in the lower left abdomen, although the location can vary. Fever, nausea, and changes in bowel habits may also occur.
Other possible causes of abdominal discomfort include gallbladder disease, urinary tract problems, gynecological conditions, and food intolerances.
Because so many conditions can produce similar symptoms, pain alone cannot establish a diagnosis.
People should pay attention to:
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Abdominal pain that continues or repeatedly returns.
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Bloating that does not improve with ordinary changes in eating habits.
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Pain associated with constipation or diarrhea.
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A persistent feeling of pressure in the lower abdomen.
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Discomfort that wakes someone from sleep.
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Abdominal symptoms accompanied by bleeding, fever, or unexplained weight loss.
Severe or rapidly worsening abdominal pain, especially when accompanied by vomiting, fever, a swollen abdomen, or an inability to pass stool or gas, requires urgent medical assessment.
The key difference is not whether abdominal discomfort happens occasionally, but whether it becomes persistent, unusual, or increasingly disruptive.
Keeping track of when symptoms occur, what foods are consumed, and whether bowel movements affect the discomfort can provide useful information during a medical consultation.