Frangulin is a natural glycoside found in the bark of buckthorn (Frangula alnus) and other species of this plant. It belongs to the anthraquinone class and is known for its laxative properties. Frangulin stimulates intestinal peristalsis, facilitating the process of defecation, so it is often used in the treatment of constipation and other problems with the gastrointestinal tract.

Frangulin works by increasing the secretion of fluid in the intestine and stimulating its contractions, which contributes to the faster passage of fecal masses. Due to these properties, buckthorn-based preparations are often used as natural laxatives. They have a milder effect compared to other laxatives and are less likely to irritate the intestinal mucosa.

However, long-term use of Frangulin or Frangulin-based drugs can lead to intestinal dependence on the laxative effect, so it is important to follow the recommended dosage and not use such drugs for too long without consulting a doctor.