Sixteen parkinsonian patients with daily fluctuations in the clinical response to levodopa have been placed on a redistribution protein diet. The diet was virtually protein-free until the evening meal and then unrestricted until bedtime. While on the redistribution protein diet, a group of patients (5 out of 16) had a clear and significant benefit from dietary therapy showing a definite reduction of diurnal motor performance fluctuations. In addition, all patients tended to show an improvement and a more constant response to levodopa treatment. A trial of redistribution protein diet appears a simple, reasonable, worthwhile approach to PD patients who begin to experience oscillating clinical response to levodopa treatment.