What side effects may occur?Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Colestid. Most common side effects may include: Constipation, worsening of hemorrhoids Less common or rare side effects may include: Abdominal bloating or distention/cramping/pain, aches and pains in arms and legs, angina (crushing chest pain), anxiety, arthritis, backache, belching, bleeding hemorrhoids, blood in stool, bone pain, chest pain, diarrhea, dizziness, drowsiness, fatigue, gas, headache, heartburn, hives, indigestion, insomnia, joint pain, light-headedness, loose stools, loss of appetite, migraine, muscle pain, nausea, rapid heartbeat, rash, shortness of breath, sinus headache, skin inflammation, swelling of hands or feet, vertigo,((((( vomiting )))), weakness