The present invention provides pharmaceutical compositions comprising Mucuna pruriens seeds or one or more Mucuna pruriens seed components, substances, fractions or mixtures or substances obtained therefrom. Furthermore, the invention relates to the use of Mucuna pruriens seed powder or one or more Mucuna pruriens components, substances, fractions or mixtures or substances obtained therefrom for the preparation of a pharmaceutical composition for preventing, alleviating or treating neurological diseases. Additionally, the invention relates to the use of Mucuna pruriens seeds for the preparation of a pharmaceutical composition for neuroprotection or neurostimulation and to methods of preparing extracts of Mucuna pruriens which can be used for the preparation of a pharmaceutical composition for treating neurological diseases. Finally, the invention relates to the use of Mucuna pruriens seeds for the preparation of a pharmaceutical composition for the treatment of Parkinson's Disease to obtain a broader therapeutic window in L-Dopa therapy, to delay a need for combination therapy, to obtain an earlier onset and longer duration of L-Dopa efficacy, and to prevent or alleviate acute and chronic L-Dopa toxicity.