Pumpkin seeds contain several major groups of active constituents: essential fatty acids, amino acids, phytosterols (e.g. beta-sitosterol) minerals, and vitamins. Other major constituents include mucilaginous carbohydrates and minerals.
Pumpkin seed oil has been used in combination with saw palmetto in two double-blind trials to effectively reduce symptoms of benign prostatic hyperplasia (BPH). Only one open label trial evaluated the effectiveness of pumpkin seed oil alone for BPH. Animal studies have shown that pumpkin seed extracts can improve the function of the bladder and urethra. This might partially account for BPH symptom relief.
Curcurbitin is a constituent in pumpkin seeds that has shown anti-parasitic activity in the test tube. Human trials conducted in China have shown pumpkin seeds to be helpful for people with acute schistosomiasis, a severe parasitic disease occurring primarily in Asia and Africa that is transmitted through snails. Preliminary human research conducted in China and Russia has shown pumpkin seeds may also help resolve tapeworm infestations. The assistance of a physician is required to help diagnose and treat any suspected intestinal parasite infections.
Two trials in Thailand have reportedly found that eating pumpkin seeds as a snack can help prevent the most common type of kidney stone. Pumpkin seeds appear to both reduce levels of substances that promote stone formation in the urine and increase levels of substances that inhibit stone formation. The active constituents of pumpkin seeds responsible for this action have not been identified.