Nasturtium

The Essentials

Benzyl isothiocyanate, the compound behind the peppery bite, fights germs in lab studies (the bacteria behind chest and urinary infections).

Rich in vitamin C and lutein (a yellow pigment linked to eye health). Pungent flavor stimulates digestion and circulation.

Traditional support for clearing damp lung congestion.

Lādan came to Persia from the Americas by way of European herbalists. Its mustard-like bite, and the way it visibly kept things from turning septic, soon earned it a place in Persian apothecaries. Modern research backs this up: benzyl isothiocyanate in the leaves and flowers really does work against the bacteria behind common chest and urinary infections.

What Else to Know

Known to botanists as Tropaeolum majus.

Sprawling annual with round, peltate green leaves and brilliant orange, yellow, or red trumpet-shaped flowers. Every aerial part — leaves, flowers, unripe seed pods — is edible and pungent.

Family: Tropaeolaceae.