Data on side effects indicated that, depending on the dose, mistletoe extracts were usually well tolerated and had few side effects.
– Cochrane Database Syst Rev. 2008 Apr 16;(2):CD003297. — Mistletoe therapy in oncology. — Horneber MA, Bueschel G, Huber R, Linde K, Rostock M.
Quantitative analysis of the extract revealed that polyphenolic compounds and the triterpenoid, oleanolic acid, are the major phytochemicals, and are proposed to be responsible for the observed diuretic effect. Oleanolic acid has been reported to possess diuretic activity with significant potassium loss in rats. In contrast to pure oleanolic acid, the extract demonstrated a valuable potassium-sparing effect. This suggests modulation of the diuretic effect of oleanolic acid by polyphenolics present in the extract. The observed dose-dependent potassium-sparing diuretic effect is a hereto unreported property of this plant.
– Pharm Biol. 2010 Apr;48(4):417-21. — Diuretic activity of squamate mistletoe, Viscum angulatum. — Jadhav RB, Bhatnagar SP, Surana SJ.
Berries have been reported to be more toxic than the leaves and stems; however the leaves and stems both contain similar toxic compounds. Fatal poisonings in children have occurred after ingestion of the berries. Mistletoe (Phoradendron serotinum) is toxic.
– CMAJ. 2006 Dec 5;175(12):1523-4. — Beware the mistletoe. — Courtemanche J, Peterson RG.