The governor of Osaka Prefecture touted the powers of gargling medicine to control the coronavirus and recommended its use, sending related shares jumping and clearing shelves of disinfectants even as some questioned the findings.

Based on limited trial on a group of 41 patients with mild symptoms, gargling with diluted povidone-iodine four times a day reduced the number of those testing positive to 9.5 percent after four days, compared with 40 percent for a group who gargled with just water, Gov. Hirofumi Yoshimura said at a press briefing on Tuesday.

Povidone-iodine is an antiseptic more commonly known as betadine. In Japan, it’s sold as gargle medicine by Shionogi & Co, using the name Isojin under license from Mundipharma, as well as by Meiji Holdings Co. Meiji, which did not immediately respond to a request for comment from Bloomberg News, saw its shares surging as much as 7.7 percent in Tokyo following the news. Shionogi rose as much as 3.6 percent.