Extracts obtained from rhizomes of ferns, which are called fernblock or “anapses”, contain calagualin and polypodin, and have been traditionally used in Central and South America as a cure of many conditions. Although some have reported a photo-protective and anti-inflammatory effect definitive evidence is lacking. Mild side effects like gastric irritation and sedation are recognized but no toxicity has been reported. Sedative effect of anti-hypertension and cardiotonic drugs as well as other plants may be increased when taken with this substance. This precludes its use with the latter medication, or, at higher dose than recommended especially by nursing mothers.