Although Metamucil is not expected to harm unborn babies, pregnant women should not use it without speaking to a health care professional first, states Drugs.com. Women who are breastfeeding should not use Metamucil without speaking to a doctor, as it is not known if it passes into the breast milk, as of 2015.
Children under the age of 6 should not take Metamucil without a doctor's recommendation, notes Drugs.com. People with stomach pain, nausea or vomiting should speak to a doctor or pharmacist before using Metamucil. Other medical conditions that could be complicated by Metamucil include trouble swallowing and a sudden shift in bowel habits that lasts for longer than two weeks.
Some people may be allergic to Metamucil, states Drugs.com. Signs and symptoms of an allergic reaction to Metamucil include difficulty breathing, hives and swelling of the tongue, throat, lips or face. Common side effects associated with Metamucil include bloating and minor changes in bowel habits.
Side effects of Metamucil that require immediate medical attention include difficulty swallowing, choking, vomiting and nausea, as well as severe stomach pain, cramping or rectal bleeding, according to Drugs.com. If a rash or constipation that lasts for longer than a week occurs, it is important to contact a physician. Other side effects not listed may also occur.