There is no comprehensive scientific literature that establishes a toxic dosage of pumpkin juice. Studies have shown a dosage of 4 mL/kg of body weight seems to cause no significant pumpkin juice side effects in most persons.

Pumpkin juice should not be combined with cucurbita, saw palmetto, and vitamin E, as some research suggests this combination promotes an increased anticoagulant effect. Infants should not drink pumpkin juice as some research supports the conclusion that ingestion of pumpkin juice in infants can lead to methemoglobinemia, due to the high nitrate content in the juice.

Other pumpkin juice side effects reported by some users include oral allergy syndrome, nausea, diarrhea, and pruritus. These effects are especially likely to be observed in the elderly, pregnant women, nursing women, or infants due to underdeveloped or compromised immune functioning. The juice should not include the leaves or seeds of the plant, which contain antinutrients such as oxalates, tannins, and cyanide.