none are recognized as toxic substances. Likewise, the plant family, Arecaceae, is not generally regarded as a toxic plant family.
Based on the limited in vitro studies to date, functionally related substances might include drugs that are inhibitors of steroid 5-α-reductase or antagonists of α1-adrenergic receptors. In general, these drugs are contraindicated for women and children (GlaxoSmithKline, 2001; Thomson PDR, 2004). Pregnant women are even cautioned not to touch broken tablets containing inhibitors of steroid 5-α-reductase (GlaxoSmithKline, 2001; Thomson PDR, 2004). Concern with these drugs are that in utero effects of inhibiting testosterone synthesis or action can deleteriously affect the external genitalia and internal reproductive organs of a male fetus (Bowman et al., 2003; Clark et al., 1990, 1993; GlaxoSmithKline, 2001).
At the present time, the weight of the scientific evidence does not suggest that the consumption of saw palmetto powdered fruit or fruit extracts poses a safety risk when consumed by men at the currently recommended doses. These conclusions are germane only to the fruit and fruit extracts presently used; introduction of new products involving different plant parts would warrant further scrutiny.
However, unlike for men, the reported adverse side effects for drugs that inhibit steroid 5-α-reductase or antagonize α1-adrenergic receptors raise concern about women who may become pregnant while using saw palmetto. This concern is mitigated somewhat by the apparent popularity of saw palmetto with men rather than women, but as noted, saw palmetto use is not limited to men. It is not evident that the testosterone pathway effects raise concerns about the safe use of saw palmetto fruit or fruit extracts in men.
Additional phytochemical analyses of the fruit and, especially, of the various fruit extracts (in which minor components would be expected to be concentrated) are needed in order to determine the presence of biologically active chemical components.
In vitro reports of cytotoxicity in prostate cancer cell lines have not been extended to other cell types in order to ascertain whether there is broader cytotoxicity.