As such, multiple studies have explored the association between PD and intestinal nervous system, intestinal glial cells, and constipation, but it is perplexing whether GDNF serum level is a risk factor in patients with PD with constipation.Here, we report an association of GDNF serum level and constipation in patients with PD using logistic regression model. Here, GDNF is linked to Parkinson disease.