Right colon:

Unexplained weakness
Anemia
Occult blood in feces
Dyspepsia
Right abdominal discomfort
Palpable abdominal mass
Weight loss

Left colon:

Change in bowel habits
Constipation
Alternating diarrhea
Gross blood in stools
Obstructive symptoms
Obstipation
Abdominal pain
Abdominal distention
Nausea
Vomiting
Weight loss