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Saw Palmetto

Saw Palmetto

Botanical Description & Habitat

Sabal serrulatum

Serenoa repens

Serenoa serrulata


Common names

Cabbage palm
Dwarf palmetto
Fan palm
Saw palmetto

Found in swampy areas and along the Atlantic coast of the United States.

Has a large underground trunk producing palmate, green, white-coated leaves. The fruit is a dark purple-to-black berry which grows in clusters and ripens from October to December.

Medicinal parts
Berries, ripe, partially-dried.

Historical Properties & Uses

Saw palmetto berries are an old American tonic
John Lloyd, a famous early American medical botanist, observed animals feeding on these berries grew sleek and fat. This same observation was made by many early settlers searching for fodder and nutritional supplements for their livestock.

Once news of these berries reached medical researchers, the berries were investigated and their effects verified. Especially in the 1870's, much research demonstrated the berry's effect on general health and disposition, tranquilization, appetite stimulation, reproductive health, and body weight.

Eventually, pressure from proponents within the medical establishment led to saw palmetto's inclusion in the National Formulary and the U.S. Pharmacopoeia. It was dropped from the USP in 1916 and the NF in 1950 as the medical profession's enthusiasm for natural agents wained.

Contributing to its demise was the fact no one had found any active principle in the herb (beyond some relatively inactive plant steroids) to account for its observed actions. Like many native American herbal remedies, it no longer received much experimental attention once the era of modern medicine arrived.

Saw palmetto berry's main effects are: on the digestive system, to stimulate appetite and provide excellent nutrition; on the reproductive system, to increase the size and secreting ability of the mammary glands, decrease ovarian and uterine irritability, relieve dysmenorrhea, ameliorate ovarian dysfunction, and relieve various diseases of the reproductive apparatus, including symptoms of inflammation, blockage, and rupture; on the prostate, to remedy enlargement and cystitis.

This berry has approval status by the German Commission E for urination problems related to benign prostatic hyperplasia (BPH).


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Method of Action

Saw Palmetto Berries Contain Plant Steroids
Dried saw palmetto berries contain high concentrations of free and bound sitosterols, including the very active beta-sitosterol. When injected under the skin of animals, they exhibited estrogenic activity.

Although no comparison can be made between this route of administration and drinking a cup of saw palmetto tea or taking a couple of capsules, one might speculate the presence of such high concentrations of sitosterols, together with other principles in the berry, forms the basis for biological activity in man. Needless to say, a great deal more research would be required to verify such a mechanism.

Drug Interactions & Precautions

Known Interactions
Since saw palmetto's diuretic action increases the renal excretion of sodium and chloride, the herb may potentiate the hyperglycemic and hyperuricemic effects of glucose-elevating agents.

Diuretics in general may potentiate the action of antihypertensive, ganglionic or peripheral adrenergic blocking drugs, tubocurarine and, to a lesser degree, norepinephrine.

Possible Interactions
In conjunction with corticotropin (ACTH) or corticosteroids, this diuretic is more prone to produce hypokalemia.

It should be noted the use of diuretics may require dosage adjustments of antidiabetic drugs. Furthermore, the diuretic action of saw palmetto may reduce renal clearance of lithium.

Prolonged use of this diuretic herb may affect certain laboratory test results such as electrolytes, and especially potassium and sodium, blood urea nitrogen (BUN), uric acid, glucose, and protein bound iodine (PBI).

The antidiabetic ability of saw palmetto may be decreased by the concomitant use of acetazolamide, oral contraceptives, corticosteroids, dextrothyroxine, epinephrine, ethanol, glucagon, and marijuana.

The antidiabetic effects of the herb may also be decreased when used in conjunction with phenothiazines, rifampin, thiazide diuretics, and thyroid hormones.

Conversely, the antidiabetic action of saw palmetto may be enhanced when used with allopurinol, anabolic steroids, chloramphenicol, clofibrate, fenfluramine, guanethidine, monoamine oxidase inhibitors (MAOI's), phenylbutazone, probenecid, and phenyramidol.

The antidiabetic action of the herb may also be enhanced when used in conjunction with salicylates, sulfinpyrazone, sulfonamides, and tetracyclines.

In the absence of other hard data, it may be assumed observable interactions occur between the many central nervous system drugs and the psychoactive principles in saw palmetto.

Safety Factors & Toxicity

The toxicity level of saw palmetto has not been determined at this time.

Saw palmetto berry has approval status by the German Commission E.


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Preparation & Administration

Three times a day

Dried fruits
0.5-1 grams

made from 1/4 tsp dried fruits

Fluid extract
1:1 in 25% alcohol, 0.6-1.5 ml

This herb has approval status by the German Commission E.

Recommended daily dosages in Germany are as follows:

1 - 2 g berry.
320 mg extract.


Blumenthal, M (Ed.): The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. American Botanical Council. Austin, TX. 1998.

Note: This Herbal Preparation information is a summary of data from books and articles by various authors. It is not intended to replace the advice or attention of health care professionals.



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Serenoa serrulata

Saw Palmetto 2.

Saw Palmetto 3.