Saw palmetto: Adverse Reactions. Significant Interactions. Pregnancy Use

The herb is generally well tolerated, with only non-specific symptoms reported, such as gastrointestinal upset, constipation, nausea, abdominal pain and diarrhea. These minor complaints are generally resolved by taking the herb in association with meals.

One large clinical study identified headache and rhinitis as the most common side-effects associated with use.

Significant Interactions

No controlled studies are available and theoretical interactions are difficult to predict, due to the poorly understood nature of the herb’s mechanism of action.


Additive effect theoretically possible — potential beneficial effect, although the clinical significance is unknown.


Theoretically, saw palmetto may reduce effectiveness of therapeutic androgens such as testosterone— observe patient for lack of drug effect.

Contraindications and Precautions

If symptoms of BPH worsen, blood is detected in the urine, or acute urinary retention occurs, professional reassessment is required.

Pregnancy Use

Use of saw palmetto during pregnancy is contraindicated due to the herb’s hormonal effects. In clinical practice, it is not used in pregnancy.