It is an object of the present invention to provide a leukotriene receptor antagonist that can be conveniently prepared from a natural source. The object has been achieved by finding that a marine product such as a squid phospholipid extract or an Akiami paste shrimp phospholipid extract contains the antagonists of BLT and CysLT1, which are leukotriene receptors. Therefore, the present invention provides a dietary composition and a pharmaceutical composition for inhibiting the activity of leukotriene receptors, containing a squid phospholipid extract or an Akiami paste shrimp phospholipid extract.
