BEIJING — Forget geopolitics: Leo Li, a 33-year-old language teacher in China, wants his essence of South Korean snail slime.

Beijing is angry at Seoul for embracing an American missile defense system intended to stop potential launches by North Korea. The South Korean conglomerate that donated a golf course to house the system has been forced to sell its Chinese stores. Chinese drivers have stopped buying Hyundais and Kias. And fewer Chinese tourists are visiting South Korea. On Thursday, South Korea unveiled tax benefits for retailers hit by the tourism drop-off and cheap loans for its automakers.

But Mr. Li’s enthusiasm for South Korean snail products helps explain a development that might surprise some people watching the relationship between China and South Korea deteriorate: Trade between the two countries is steadily rising.

“I support my country and love my country, but I don’t think this should affect my consumption decisions,” Mr. Li, who once studied in South Korea, said by phone from the southern city of Guiyang.