The present invention relates to an oral dosage form comprising gamma-aminobutyric acid (GABA) and pharmaceutically acceptable excipients, wherein 100% of the GABA is released within 0.25-5 hours in 0.01 M HCl at 37° C. in a USP dissolution apparatus 2. The invention further relates to specific dosage forms, methods for treatment of autoimmune diseases with the dosage form, as well as use of the dosage form in such methods.