The external air-layer fabric is woven with an anti-microbial fabric making it difficult for nasties like bacteria, mould, viruses and dustmites to cling onto and grow within the fabric. The anti-bacterial shield keeps your Sleepybelly fresher and safer for longer, although regular washing (just like a normal pillow) is recommended.Our fabric is a Bamboo/Polyester blend and isn’t treated. It gets its antimicrobial protection through the naturally occuring Bamboo Kun which is the natural antimicrobial agent found in bamboo.Our fabric is also OEKO-TEXT Standard 100 certified, meaning it has been tested to ensure it contains no nasties!