A previous questionnaire study suggests an increased chocolate consumption in Parkinson's disease (PD). The cacao ingredient contains caffeine analogues and biogenic amines, such as β-phenylethylamine, with assumed antiparkinsonian effects. We thus tested the effects of 200 g of chocolate containing 80 % of cacao on UPDRS motor score after 1 and 3 h in 26 subjects with moderate non-fluctuating PD in a mono-center, single-dose, investigator-blinded crossover study using cacao-free white chocolate as placebo comparator. At 1 h after chocolate intake, mean UPDRS motor scores were mildly decreased compared to baseline in both treatments with significant results only for dark chocolate [-1.3 (95 % CI 0.18-2.52, RMANOVA F = 4.783, p = 0.013¸ Bonferroni p = 0.021 for 1 h values)]. A 2 × 2-cross-over analysis revealed no significant differences between both treatments [-0.54 ± 0.47 (95 % CI -1.50 to 0.42), p = 0.258]. Similar results were obtained at 3 h after intake. β-phenylethylamine blood levels were unaltered. Together, chocolate did not show significant improvement over white cacao-free chocolate in PD motor function.