PURPOSE: To provide a processed seaweed food containing a sterile variant of sea lettuce (Ulva pertusa) as a main component and useful as a hypotensor, a constipation remedying agent and a cholesterol depressant free from side effects.

CONSTITUTION: Collected raw leaf of a sterile variant of sea lettuce is washed with seawater and/or fresh water, dried, cut into small pieces and subjected to preliminary drying at a low temperature (40-50°C) for 2-3hr. The preliminarily dried product is irradiated with far infrared rays to effect the main drying at a high temperature (70°C) for 1hr and formed in the form of tablets, pellets or granules with a tableting machine, a granulation machine or a pelletizer.