Isabgol

Isabgol, the papery husk of psyllium seed grown mostly in Gujarat, a soluble fibre that swells with water and one of the best-studied aids to regularity.

Plantago ovata is a small annual herb with narrow leaves and short flower spikes, grown above all in Gujarat; India supplies most of the world's psyllium. The husk is the thin outer coat of the seed, milled off as pale, papery flakes that soak up water and form a soft gel.

That gel makes isabgol a bulk-forming fibre: it softens the stool, adds volume and supports regular bowel movements. The evidence is strong, and the European Medicines Agency recognises ispaghula husk for habitual constipation on well-established use. Regulators also say it should go down with plenty of liquid, spaced from other medicines, and not be used by anyone who has difficulty swallowing.

• Bowel regularity
• Bulk-forming fibre
• Soluble fibre
• Cholesterol support