China's State Food and Drug Administration (SFDA) has ordered a "serious investigation" into two kinds of bath products that reportedly gave children skin diseases.

The order came after recent reports accused the body wash and lotion used by bathhouse chain Tian Po Po Xi Jiu Tang, or, literally, "Grandma Tian's Bathhouse," in southwest China's Sichuan Province of having "caused severe body damages," according to a SFDA statement released Tuesday.

The bathhouse chain, with a history of some 70 years, was first established in Sichuan's capital Chengdu and was listed as a part of the city's Intangible Cultural Heritage in 2009.

The licensed bathhouse claimed to use bath products developed by its own Chinese herbal medicine recipes that protected children from various skin ailments and other diseases, such as eczema, colds, and constipation.

However, an unknown number of children suffered pustular psoriasis, a chronic skin irritation characterize by raised bumps, after washing at the bathhouse chain and using the two products, according to reports.

Sichuan's provincial food and drug administration bureau previously deemed the two products to be "fake drugs" based on an initial investigation by the local police and food and drug authorities, the statement said.

The SFDA urged local food and drug supervision departments across the country to monitor and check the two products sold by the bathhouse chain within their regions, and vowed to punish any violations of laws and regulations.