For most people, powdered cellulose is well tolerated and may even offer benefits similar to dietary fiber. However, excessive intake, often from consuming large amounts of processed foods, may lead to gastrointestinal discomfort such as bloating, gas, constipation, or diarrhea. Rarely, allergic reactions like rash, itching, or difficulty breathing have been reported, primarily in individuals with heightened sensitivities. While concerns have been raised about cellulose derivatives like carboxymethylcellulose potentially disrupting gut bacteria or triggering inflammation with long-term high intake, such effects have not been clearly linked to unmodified powdered cellulose.