A method of treating a patient comprises orally administering a solid oral dosage form comprising a core comprising a non ionic polymer matrix a first amount of ondansetron dispersed within the matrix and a salt dispersed within the matrix wherein the first amount of ondansetron ranges from about 9 mg to about 28 mg a first seal coat surrounding the core wherein the first seal coat is comprised of a non ionic polymer matrix and an immediate release drug layer surrounding the first seal coat and comprising a non ionic polymer and a second amount of ondansetron dispersed therein wherein the second amount of ondansetron ranges from about 3 mg to about 8 mg wherein release of ondansetron from the solid oral dosage form provides exposure to ondansetron for a minimum period of 16 hours so as to result in a reduction in frequency of vomiting nausea diarrhea or a combination thereof.
