Digitalis (foxglove) belongs to the family Scrophulariaceae. The fresh leaves are dried at a temperature below 60°C. The leaves should contain not more than 5% of moisture.

Digitalis is a biennial or perennial herb of about 1 to 2 meters. It is propagated by seeds of the selected strain, containing high glycosidal content.

The leaves are picked up in the afternoon during August and September and are immediately brought to the drying centre and dried in vacuum driers.

The dried leaves (containing not more than 5% of moisture) are packed into the air-tight containers, with suitable dehydrating agent.

The activity of the leaves is due to the glycoside. The presence of moisture and the enzymes (i.e. digipurpuridase and oxidase) cause deterioration of glycosides. If the leaves are dried above 60 degree C, potency is lost due to chemical degradation.