The present invention provides pharmaceutical suspensions of D-methionine in which the aqueous solubility of D-methionine is exceeded, thereby allowing oral administration of higher doses. The present invention also provides processes for preparing these suspensions. The present invention further provides methods for preventing, treating, or ameliorating oral mucositis, hearing loss due to chemotherapy, antibiotics and noise, neuronal damage due to various CNS disorders and injuries, and anthracycline toxicity.