Bromelain is a digestive enzyme that naturally occurs in pineapple. Bromelain specifically helps break down proteins, but research has found wide-reaching benefits of this enzyme, from your gut to your heart. Bromelain may reduce the duration of nasal congestion for children with colds, improve physical function and reduce stiffness in individuals with knee pain, and decrease the amount of pro-inflammatory cytokines in cells from individuals with inflammatory bowel disease.