PROBLEM TO BE SOLVED: To provide a drug or a food and drink product which routinely enables prolonged administration and exhibits a safe and sufficient urease activity inhibition effect.SOLUTION: A urease activity inhibitor includes an extract of a plant that belongs to the family Sapindaceae. "Lychee" of a raw material of the urease activity inhibitor is a fruit tree of an evergreen high tree that belongs to the family Sapindaceae and is scientifically named "Litchi chinensis" and the Japanese name is "Reishi" or "Raichi", and the lychee is native to the southern part of China and is cultivated in a tropical region or a subtropical region. Further, "Rambutan" belongs to the same family Sapindaceae as lychee and is scientifically named "Nephelium lappaceum" and is native to Southeast Asia and a medium to large tropical fruit tree. As the lychee extract and the rambutan extract used here, commercially available ones can be utilized. Without reference to the form of the urease activity inhibitor, any form including normal drugs such as a tablet sweet, a candy, a granule, and a drink, quasi drugs, and food and drink products can be employed.
